Symposium Organizers
Yuan Yang, Columbia University
Mauro Pasta, University of Oxford
Kristin Persson, University of California, Berkeley
Jia Zhu, Nanjing University
Symposium Support
BICI Collaborative Innovation
Bio-Logic USA
Gotion Inc.
Jiangsu Qingtao Energy S&
T Co., Ltd.
ES2.3: Alkaline Metal Anodes
Session Chairs
Kristin Persson
Hailiang Wang
Wednesday AM, April 19, 2017
PCC North, 200 Level, Room 224 A
9:30 AM - *ES2.3.01
Battery 500Wh/Kg: Reviving Lithium Metal Anode through Materials Design
Yi Cui 1
1 , Stanford University, Stanford, California, United States
Show AbstractLithium metal anodes offer the highest specific capacity and lowest potential for high energy batteries. It is the most important anode to enable Li-S and Li-O2 batteries. However, there are many materials challenges associated with Li metal, which reduce the battery cycling life and cause safety concerns. We believe that the root causes of Li metal challenge are from its hostless nature of deposition and stripping and high chemical reactivity. In this talk, I will be present how we design three-dimensional hosts and construct stable interface for Li metal anodes.
10:00 AM - *ES2.3.02
Lithium Metal Anodes and Rechargeable Li Metal Batteries
Jiangfeng Qian 2 1 , Brian Adams 1 , Jianming Zheng 1 , Wu Xu 1 , Ji-Guang Zhang 1
2 , Wuhan University, Wuhan China, 1 , Pacific Northwest National Laboratory, Richland, Washington, United States
Show AbstractRechargeable metal batteries, such as Li metal batteries are considered the “holy grail” of energy storage systems. However, dendritic metal growth and limited Coulombic efficiency (CE) during metal deposition/stripping have prevented their practical applications in rechargeable batteries. In this presentation, we will first give an overview on the recent development in this field, then discuss our recent works in this field. During the last a few years, we have developed several approaches to suppress metal dendrite growth and enhance the Coulombic efficiency (CE) of metal deposition/stripping processes. Several electrolyte additives, including CsPF6, RbPF6, and trace-amount of H2O have been found to be effective for achieving dendrite-free Li metal deposition in LiPF6-based electrolytes. Furthermore, we have developed a highly concentrated electrolytes composed of the lithium bis(fluorosulfonyl)imide (LiFSI) salt and 1,2-dimethoxyethane (DME) solvent which enables high rate cycling of Li metal anode at high CE (up to 99.1 %) without dendrite growth. It is demonstrated that a Li|Li cell can be cycled at high rates (10 mA cm-2) for more than 6,000 cycles with no increase in the cell impedance and no dendritic Li growth. At last, we report for the first time an anode-free rechargeable lithium battery based on a Cu||LiFePO4 cell structure with an extremely high CE (> 99.8%). This results from the utilization of both an exceptionally stable electrolyte and optimized charge/discharge protocols which minimize the corrosion of the in-situ formed Li metal anode. Further development of this technology will accelerate the commercialization of next generation of Li metal batteries.
10:30 AM - ES2.3.03
High Performance Lithium Metal Anode with a Soft and Flowable Polymer Coating
Jeffrey Lopez 1 , Guangyuan Zheng 1 2 , Chao Wang 1 , Allen Pei 1 , Zhenan Bao 1 , Yi Cui 1
1 , Stanford University, Stanford, California, United States, 2 , Institute of Materials Research and Engineering, Singapore Singapore
Show AbstractThe future development of low cost, high performance electric vehicles depends on the success of next-generation lithium-ion batteries with higher energy density. The lithium metal anode is key to applying these new battery technologies. However, the problems of lithium dendrite growth and low coulombic efficiency have proven to be difficult challenges to overcome. Fundamentally, these two issues stem from the instability of the solid electrolyte interphase (SEI) layer, which is easily damaged by the large volumetric changes during battery cycling. In this work, we show that by applying a highly viscoelastic polymer to the lithium metal anode, the morphology of the lithium deposition became significantly more uniform. At a high current density of 5 mA/cm2 we obtained a flat and dense lithium metal layer, and we observed stable cycling Coulombic efficiency of ~97% maintained for more than 180 cycles at a current density of 1 mA/cm2.
ES2.4: Group VI Cathodes—S and Se I
Session Chairs
Kristin Persson
Hailiang Wang
Wednesday PM, April 19, 2017
PCC North, 200 Level, Room 224 A
11:15 AM - *ES2.4.01
Dynamically and Statically Stable Metal-Sulfur Batteries with High Sulfur Loading
Arumugam Manthiram 1
1 , University of Texas at Austin, Austin, Texas, United States
Show AbstractWith an aim to increase the energy density and lower the cost, sulfur cathodes have become appealing in recent years for rechargeable batteries. However, the sulfur cathodes suffer from poor dynamic (cycle life) and static (self-discharge) stability, arising from the severe diffusion and shuttling of dissolved polysulfides between the sulfur cathodes and the metal (lithium or sodium) anodes. Also, the electrochemical utilization of sulfur is hampered by the poor electronic conductivity of and low ionic diffusion in sulfur, necessitating the incorporation of a significant amount of carbon into sulfur electrodes and a large amount of liquid electrolyte into metal-sulfur cells. In fact, it is often easy in the literature to obtain greatly improved performance by using a low sulfur content, low sulfur loading, or low sulfur mass in a cathode. The high amounts of carbon and liquid electrolyte along with a low sulfur loading per unit area in the cell defeat the energy-density advantages of sulfur cathodes and the prospects of metal-sulfur cells replacing the current lithium-ion technology. Moreover, the traditional cathode configuration borrowed from the commercial insertion-compound cathodes may not allow the pure sulfur cathode to put its unique materials chemistry to good use due to the very different battery chemistries between the solid insertion-compound oxide cathodes and the electrochemical conversion-reaction sulfur cathodes.
Recognizing the criticality of increasing the sulfur loading and decreasing the electrolyte amount to be competitive with the current lithium-ion technology, this presentation will focus on unique approaches in engineering the sulfur cathodes with high-sulfur loading and low electrolyte amount. The strategies include (i) confining pure sulfur powder between porous carbon nanofiber multilayers with a layer-by-layer approach, (ii) covering the active sulfur material with a multiwall carbon nanotube thin film with an edge encapsulation method, and (iii) employing nanocomposite electrodes consisting of sulfur and electrochemically active metal sulfides. These sulfur cathode engineering approaches are then integrated with polysulfide-trapping interlayers, multi-functional separators, solid electrolyte membranes, and alkali-metal anode protection strategies developed in our group for suppressing polysulfide migration and alkali-metal dendrite growth. The approaches allow the fabrication of cells with sulfur contents of ~ 70 wt.%, sulfur loadings of up to 30 mg/cm2, areal capacities of > 10 mAh/cm2, and capacities of ~ 1,000 mAh/g with good cycle life (dynamic stability) and low self-discharge rate (static stability).
11:45 AM - ES2.4.02
Design Stable Room-Temperature Metal-Sulfur Batteries
Shuya Wei 1 , Lynden Archer 1
1 , Cornell University, Ithaca, New York, United States
Show AbstractHigh-energy and inexpensive rechargeable battery systems based on earth-abundant materials are important for both mobile and stationary energy storage technologies. Rechargeable sodium-sulfur (Na-S) batteries that are able to operate stably at room temperature are among the most sought-after of these platforms because these cells take advantage of a two-electron-redox process to yield high storage capacity from inexpensive electrode materials. Realization of practical Na-S batteries has been fraught with multiple stubborn problems ranging from unstable electrodeposition of sodium during battery recharge to rapid loss of the active cathode material by dissolution into the electrolyte. In this study, we develop a room temperature Na-S battery that uses a sodium metal anode, a microporous carbon-sulfur composite cathode, and a liquid electrolyte containing a functional imidazolium-based ionic liquid as a deposition stabilizer. We show that the Na-S cells with this configuration can cycle stably for over 100 cycles at 0.5C (1C = 1675 mAh/g) with 600 mAh/g reversible capacity and nearly 100 percent Coulombic efficiency. By means of spectroscopic and electrochemical analysis, we find that the high stability and reversibility of the cells stem from at least two sources related both to the cathode and anode. First, the functional ionic liquid spontaneously forms a Na-ion conductive film on the anode, which appears to stabilize deposition of sodium by reducing the electric field near the electrode and prevent electrolyte decomposition and depletion. Second, on the cathode side, microporous carbon materials play a key role that can constrain the electrochemical reaction between sodium ion and sulfur to the solid state without the formation of the intermediate soluble sodium polysulfide species. This combination of electrolyte and carbon substrate are shown to provide sufficiently strong association of sulfur in the cathode and at the same time stabilize the surface of the highly reactive sodium metal anode.
12:00 PM - ES2.4.03
Empowering the Performance of Lithium Sulfur Batteries via Development of Integrated Polysulphide Reservoirs
Sarish Rehman 1 , Yanglong Hou 1 , Kishwar Khan 2
1 Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing China, 2 Department of Chemical & Biomolecular Engineering (CBME), The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon Hong Kong
Show AbstractLithium–sulfur batteries (LSBs) are of immense importance because of its high theoretical energy density. Among the existed myriad energy-storage technologies, LSBs show the appealing potential for the ubiquitous growth of next-generation electrical energy storage application. It hold unparalleled theoretical energy density of 2600 Wh/kg, that is almost sixth fold larger than that of conventional lithium-ion batteries (LIBs). Despite holding high theoretical capacity, the practical application is still plagued by its rapid capacity decay caused by the polysulfide shuttle, insulating nature of sulfur and polysulfides products. To tackle the hurdles associated with LSBs, exciting progress has been made, however still it is great challenge to mitigate the problems of LSBs and enhance its electrochemical performance. In order circumvent the aforementioned challenges, we design an innovative nanostructure, namely silicon/silica (Si/SiO2) crosslink with hierarchical porous carbon spheres (Si/SiO2@C), and use it as a new and efficient sulfur host to prepare Si/SiO2@C-S hybrid spheres to solve the hurdle of the polysulfides dissolution. We employ the concept of both physical and chemical adsorptions of polysulfides via the carbon and Si/SiO2 of developed hybrid spheres, respectively. Different from the traditional porous carbon structures, the developed hybrid spheres afford the intriguing structural advantages. As a result of multitude structural advantages of the developed hybrids spheres, it acts as efficient polysulfides reservoir for enhancing lithium sulfur battery (LSB) in the terms of capacity, rate ability and cycling stability via combined chemical and physical effects.
The present work highlights the vital role of the introduction of new class of hybrid nanostructure cathodes in boosting the performance of LSBs.
References:
S. Rehman, S. Guo and Y. Hou, Rational Design of Si/SiO2@Hierarchical Porous Carbon Spheres as Efficient Polysulfide Reservoirs for High-Performance Li–S Battery, Advanced Materials.2016, 28, 3167–3172.
S. Rehman, S. Guo and Y. Hou, 3D Vertically Aligned and Interconnected Porous Carbon Nanosheets as Sulphur Immobilizers for High Performance Lithium-Sulphur Batteries, Advanced Energy Materials (DOI:10.1002/aenm.201502518).
12:15 PM - ES2.4.04
Towards an Efficient Current Collector for Ceramic-S Composite Cathodes in Lithium Sulfur Batteries
Priyanka Bhattacharya 2 , Nickolas Vallo 3 , Ashish Gogia 3 , Vijayakumar Murugesan 1 , Ashleigh Schwarz 4 , Apparao Rao 5 , Anthony Childress 5 , Guru Subramanyam 3 , Jitendra Kumar 2
2 Energy Technologies and Materials, University of Dayton Research Institute, Dayton, Ohio, United States, 3 Electrical and Computer Engineering, University of Dayton, Dayton, Ohio, United States, 1 Physical Sciences, Pacific Northwest National Laboratory, Richland, Washington, United States, 4 , Environmental Molecular Sciences Laboratory, Richland, Washington, United States, 5 Physics and Astronomy, Clemson University, Clemson, South Carolina, United States
Show AbstractLithium-sulfur (Li-S) batteries are promising energy-storage systems, offering up to five-fold increase in energy density as compared with present state-of-the-art Li-ion batteries, thus potentially serving as a means to meet the growing demand for safe, environmentally friendly, high-energy density applications. Despite its advantages, Li-S batteries have yet to be commercialized owing to a few unresolved issues such as poor S loading, lithium polysulfide (LiPS) dissolution in the liquid organic electrolyte resulting in active material shuttling, and instability of Li metal. Most recent research has focused on advancing the S cathode by engineering the carbon host and designing functional binders. However, very little attention has been paid to the cathode current collector (CC). It is well known that aluminum (Al) and stainless steel CCs easily corrode under electrochemical potential in the presence of LiPS. Hence, it is essential to select more appropriate CCs. Here, we will present our recently developed high-energy density and efficient S cathode composite with graphene and solid ceramic electrolyte (lithium aluminum germanium phosphate, LAGP). Without any special efforts to engineer the cathode, we were able to obtain very favorable cycling stability. This was attributed to the high electronic conductivity of the graphene enwrapping S, and the high ionic conductivity of LAGP well dispersed in the cathode composite, which results in higher S utilization, lower cell polarization and enhanced electrolyte wetting. In addition, a porous and functionalized carbon nanotube (CNT) based CC aids in preventing the corrosion of conventional Al CCs by LiPS, and arrests the dissolution of LiPS while providing enhanced electronic conductivity to the cathode materials. The favorable chemical resistivity and porosity of the CNT CCs ensure better adhesion and interfacial interactions between the functional groups on CNT and carbon/S particles as well as LiPS. This unique combination of a high energy density cathode and efficient CC served as a promising electrochemically stable composite S cathode with high initial cathode capacities (>1650 mAh g-1 at C/20, 1C=1675 mAh g-1, 98% S utilization), and a cycling stability for >200 cycles with >600 mAh g-1 at C/5. It is anticipated that by using such scalable, novel cathode composites, this research will lead to the development and commercialization of high energy density, safe and long-cycle life Li-S batteries.
12:30 PM - ES2.4.05
A Facile Soft-Template Synthesis of Ultrahigh Surface Area Nitrogen-Doped Mesoporous Carbon Nanospheres for High Performance Lithium-Sulfur Batteries
Zhiwei Tang 1 , Hongji Xu 1 , Xidong Lin 1 , Dingcai Wu 1 , Ruowen Fu 1
1 , Sun Yat Sen University, Guangzhou China
Show AbstractWe firstly propose a facile, simple one-step method to prepare a class of well-defined polymer nanopheres which base on self-assembly of PS-b-PEO block polymers and aniline (ANi)-pyrrole (Py) comonomers, and then obtain the nitrogen-doped mesoporous carbon nanospheres (NMCS) through direct carbonization which possess ultrahigh surface area (ca. 2520 m2 g-1) and large mesopores (ca. 18.6 nm). The surface area of resultant NMCS can be tailored by simplely changing carbonization condition. The ultrahigh surface area and large mesopores of the N heteroatom-doped carbon nanospheres render serving as excellent sulphur host materials for lithium-sulphur batteries and show a widely potential in energy storage fields. The NMCS-S cathode deliver an initial specific capacity of 1438 mAh g-1 at 0.2 C and exhibited a robust cycling performance for 1000 cycles with 83.5% capacity retention at 2 C, better than most porous carbon and other organic-inorganic host materials. The synthesis strategy may provide a new direction for fabricating unusual ultrahigh-surface-area carbonaceous materials with potential for energy storage, catalysis, medicine, adsorption and separation applications.
12:45 PM - ES2.4.06
Copolymer Sulfur Cathodes for High Capacity Lithium Ion Batteries
Jingjing Liu 1 , Brennan Campbell 1 , Changling Li 1 , Zafer Mutlu 1 , Rachel Ye 2 , Jeffrey Bell 1 , Yiran Yan , Cengiz Ozkan 1 2 , Mihri Ozkan 1 3
1 Material Science & Engineering, University of California, Riverside, California, United States, 2 Mechanical Engineering, University of California, Riverside, California, United States, 3 Electrical and Computer Engineering, University of California, Riverside, California, United States
Show AbstractNowadays, energy storage is playing an essential role in the field of consumer electronics, electric vehicles, aerospace applications, and stationary energy storage. Lithium ion batteries have been the key technology of the rechargeable batteries, considering their high energy density, low operation voltage, and low rate of self-discharge. However, the capacity of commercial lithium ion battery is still limited by the low capacity of the prevailing cathode material (LiCoO2, ~274 mAh/g). To overcome the issue, sulfur, with the capacity of 1672 mAh/g, receives more and more attentions as a promising material for the next generation cathode recently. To fully realize the potential of sulfur-based cathode material, we synthesized the chemical stable and scalable copolymer sulfur materials as the cathodes of lithium batteries. The copolymer sulfur material was made from 1,3-Diethynylbenzen and element sulfur via invers vulcanization. The copolymer sulfur cathode showed good stability with initial capacity ~1100 mAh/g. With the characterization techniques of EDS, XPS, SEM, and Raman spectroscopy, the physical and chemical properties of this copolymer sulfur material were demonstrated. The electrochemical properties of the copolymer sulfur cathode were tested by Bio-Logic.
ES2.5: Group VI Cathodes—S and Se II
Session Chairs
Wednesday PM, April 19, 2017
PCC North, 200 Level, Room 224 A
2:45 PM - *ES2.5.01
Challenges in Li-S Batteries—Thick Cathode and Anode Corrosion
Jie Xiao 1 , Joshua Lochala 1
1 , University of Arkansas, Fayetteville, Arkansas, United States
Show AbstractIn recent years, lithium sulfur (Li-S) batteries have garnered drastic research interest for both transportation and large-scale (grid) energy storage applications mainly because of this electrochemical couple's high theoretical gravimetric energy density which is projected to be twice that of the state-of-art lithium-ion (Li-ion) batteries and the potential for a greatly reduced battery cost. However, before the market penetration of Li-S batteries, many challenges must be addressed including poor cycling stability, low round-trip efficiency and severe self-discharge, all of which are rooted in the dissolution of long-chain polysulfide species. As one of the most promising next-generation battery technologies, the Li-S system has been revisited worldwide and the number of publications has increased exponentially. With the understanding from atomic level on Li-S reaction mechanism has been continuously gathered, it is needed to evaluate Li-S batteries at a more practical environment to ensure the knowledge is adaptable by industry. This talk will discuss the main challenges towards the design of a high-energy Li-S battery and how to address them from materials chemistry and science point of view.
3:15 PM - ES2.5.03
High Loading Li-S and Li-Se Batteries towards Commercialization—Material, Fabrication and Cell Design
Fang Dai 1 , Qiangfeng Xiao 1 , Li Yang 1 , Mei Cai 1
1 , General Motors, Warren, Michigan, United States
Show AbstractThe merging storage applications, such as grid storage system, require development of novel energy storage systems with improved efficiency and reduced cost. Lithium-sulfur battery (Li-S) has been recognized as one promising system beyond conventional Li-ion system due to its high gravimetric energy density and low material cost, which is superior to most of current Li-ion batteries. In recent years, lithium-selenium chemistry also drew attention due to its similarity, as well as few advantages beyond Li-S system.
However, some major issues of Li-S system, such as shuttling effect, are still not fully surpassed after years’ development. In addition, conflict also exists between the overall electrochemical performance and active material loading. Other issues such as electrolyte amount are also critical. Both chemistry and engineering research and development are necessary to address all those issues that delay the large-scale industrial manufacturing and commercialization of the Li-S batteries.
In order to eventually push for further industrial manufacturing and commercialization, we have spent years working on the Li-S and Li-Se chemistry for balanced solution. Here we’d like to share some results from our works on the Li-S and Li-Se systems. A well-engineered carbon framework will be introduced and discussed for high sulfur loading electrodes fabrication. Corresponding critical parameters, as well as the performance evaluation of the obtained high loading electrode will be also discussed. The high loading of S on both material (> 75 wt%) and electrode level (> 70 wt %, > 3 mAh/cm2) enables a much improved electrochemical performance of the large size pouch format Li-S cell. With the similar electrode fabrication, high loading Se electrodes were also fabricated and evaluated in Li-Se cell. In addition, influence of polymer binder and electrolyte on the optimized electrodes on both Li-S and Li-Se systems will be discussed. Besides the cell performance, we’ll also share the principle on material screening, cell fabrication and cell design.
4:30 PM - ES2.5.04
In Operando Synchrotron Multi-Modal Investigation for Structural and Chemical Evolution of Metal Sulfide Additives in Li-S Battery
Ke Sun 3 , Chonghang Zhao 1 , Garth Williams 2 , Jianming Bai 2 , Eric Dooryhee 2 , Juergen Thieme 2 , Yu-chen Chen-Wiegart 2 1 , Hong Gan 3
3 Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York, United States, 1 Materials Science and Engineering, Stony Brook University, Stony Brook, New York, United States, 2 National Synchrotron Light Source - II, Brookhaven National Laboratory, Upton, New York, United States
Show AbstractLi-S batteries hold great promise as an alternative battery technology due to its high energy density, however the technology still presents several challenges. Especially, the two end products during the operation of a Li-S battery, sulfur and Li2S, are both electronic insulators, which causes serious polarization during operation and greatly limits the power capacity of the battery. This issue is critical for thick sulfur electrodes (up to 200 microns), which is a must for commercialization. Targeting this challenge, we want to improve the sulfur cell electrochemical performance by introducing capacity-contributing conductive additives, such as CuS, FeS2 and TiS2. The concept of capacity-contributing and power improvement has been demonstrated. However, complicated interactions at the system level are accompanied by some detrimental effects, whose reaction mechanisms are unclear. In particular, some metal sulfide additives suffer from undesired side-reactions, such as dissolution in CuS and FeS2. The interaction of the Sulfur and the metal sulfide in the hybrid cell also remains unclear.
To address the fundamental mechanisms in these systems, we utilized in operando synchrotron characterization methods to study the metal sulfide structural and chemical evolution during lithiation and de-lithiation. In operando x-ray fluorescence imaging with sub-µm spatial resolution reveals the onset of the transition metal ion dissolution at the hybrid cathode and its re-deposition at the anode, elemental distribution during the dissolution/re-deposition and their correlation with the electrochemical reactions. Furthermore, x-ray absorption spectroscopy and in operando x-ray diffraction were applied to reveal the structural and chemical evolution during the reactions. Experiments were conducted at the state-of-the art National Synchrotron Light Source – II, with the same in operando battery cell used across different beamlines, demonstrating its multi-modal compatibility. We will present our understanding of the structural and chemical evolution of the system and the proposed reaction mechanisms, which shed light on potential applications and future development directions.
4:45 PM - ES2.5.05
Molybdenum Polysulfide Chalcogels as High-Capacity, Anion-Redox-Driven Electrode Materials for Li–Ion Batteries
Vicky Doan-Nguyen 1 , Suryasubrahmanyam Kota 2 , Megan Butala 1 , Jeffrey Gerbec 1 , Saiful Islam 2 , Katherine Kanipe 1 , Catrina Wilson 1 , Mahalingam Balasubramanian 3 , Kamila Wiaderek 3 , Olaf Borkiewicz 3 , Karena Chapman 3 , Peter Chupas 3 , Martin Moskovits 1 , Bruce Dunn 4 , Mercouri Kanatzidis 2 , Ram Seshadri 1
1 , University of California, Santa Barbara, Santa Barbara, California, United States, 2 , Northwestern University, Evanston, Illinois, United States, 3 , Advanced Photon Source, Lemont, Illinois, United States, 4 , University of California, Los Angeles, Los Angeles, California, United States
Show AbstractSulfur cathodes in conversion reaction batteries offer high gravimetric capacity but suffer from parasitic polysulfide shuttling. We demonstrate here that transition metal chalcogels of approximate formula MoS3.4 achieve high gravimetric capacity close to 600 mAh g−1, as electrode materials for lithium-ion batteries. Transition metal chalcogels are amorphous, and comprise polysulfide chains connected by inorganic linkers. The linkers appear to act as a “glue” in the electrode to prevent polysulfide shuttling. The Mo chalcogels function as electrodes in carbonate– as well as ether–based electrolytes, which further provides evidence for polysulfide solubility not being a limiting issue. We employ X-ray spectroscopy and operando pair distribution function techniques to elucidate the structural evolution of the electrode. Raman and X-ray photoelectron spectroscopy track the chemical moieties that arise during the anion-redox-driven processes. We find the redox state of Mo remains unchanged across the electrochemical cycling and correspondingly, the redox is anion–driven.
5:00 PM - *ES2.5.06
Cathode Materials Design and Surface Chemistry for Stable Cycling Lithium-Sulfur Batteries
Hailiang Wang 1
1 , Yale University, West Haven, Connecticut, United States
Show AbstractRechargeable Li-S batteries are potentially high-energy-density and low-cost electrochemical devices for future electric transportation and stationary energy storage, however the short cycle life imposes a strong constraint on their applications. On the cathode side, poor cycling stability is mainly caused by uncontrolled diffusion of lithium polysulfide intermediates. Our research aims to address this key challenge by realizing rational design of high-performance sulfur cathodes based on molecular level understanding of the chemical interactions at material/polysulfide interface.
We have developed NiFe2O4 nanosheets anchored on carbon nanotubes (CNTs) as a carbon/inorganic hybrid scaffold to host sulfur. The CNT/NiFe2O4-S material exhibits balanced high performance with respect to specific capacity, rate capability and cycling stability. We have also found that the adsorption of polysulfides on the NiFe2O4 surface is chemical in nature and morphology dependent.
Thus far the majority of the reported sulfur host materials are inorganic solids. We consider metal-organic complexes as more efficient polysulfide confining materials because of their molecular nature. We investigated ferrocene (Fc) as a polysulfide confining agent to promote long cycle Li-S batteries. We find Fc non-covalently attached on graphene oxide (GO) is effective for suppressing lithium polysulfide shuttling and consequently capacity fading. Covalently linking Fc molecules to GO can further optimize the electrochemical performance. With combined spectroscopic studies and theoretical calculations, we further identify that the effective polysulfide binding originates from favorable cation-π interactions between the Li ions of lithium polysulfides and the negatively charged cyclopentadienyl ligands of Fc.
We have also made progress in developing a novel ultrathin composite thin film comprised of naphthalimide-functionalized poly(amidoamine) G4 dendrimer and mildly-oxidized GO as a new polysulfide confining surface layer for high-performance and long-cycle sulfur cathodes. Combining the dendrimer structure that can confine polysulfide intermediates chemically and physically together with the GO that renders the film robust and thin, the composite film enables stable cycling of sulfur cathodes without compromising the energy and power densities.
Improving the cycling stability of sulfur cathodes requires immobilizing the lithium polysulfide intermediates as well as accelerating their redox kinetics. While many materials have been explored for trapping polysulfides, the capability of promoting polysulfide redox has been much less noticed. We for the first time report on transition metal phosphides as effective host materials to enhance both lithium polysulfide adsorption and redox. Integrating MoP-nanoparticle-decorated carbon nanotubes with sulfur deposited on GO, we enable Li-S battery cathodes with substantially improved cycling stability and rate capability.
5:30 PM - ES2.5.07
Exceptional Energy and New Insight with Sodium—Selenium Battery Based on Carbon Nanosheet Cathode and Pseudographite Anode
David Mitlin 1
1 , Clarkson University, Edmonton, Alberta, Canada
Show AbstractWe created a unique sodium ion battery (NIB, SIB) cathode based on selenium in cellulose-derived carbon nanosheets (CCN), termed Se-CCN. The elastically compliant two-dimensional CCN host incorporates a high mass loading of amorphous Se (53wt.%), which is primarily impregnated into the 1 cm3g-1 of the nanopores. This results in facile sodiation kinetics due to short solid-state diffusion distances and large charge transfer area of the nanosheets. The architecture also leads to an intrinsic resistance to polyselenide shuttle and to disintegration/coarsening. As a Na half-cell, the Se-CCN cathode delivers a reversible capacity of 613 mAh g-1 with 88% retention over 500 cycles. The exceptional stability is achieved employing a standard electrolyte (1M NaClO4 EC-DMC), without secondary additives or high salt concentrations. The rate capability is also superb, achieving 300 mAhg-1 at 10C. Compared to recent state-of-the-art literature, the Se-CCN is the most cyclically stable and offers the highest rate performance. As a Se-Na battery, the system achieves 992 Wh/kg at 68 W/kg and 384 Wh/kg at 10144 W/kg (by active mass in cathode). We are the first to fabricate and test a Se-based full NIB, which is based on Se-CCN coupled to a Na intercalating pseudographitic carbon anode (PGC). It is demonstrated that the PGC anode increases its structural order in addition to dilating as a result of Na intercalation at voltages below 0.2 V vs. Na/Na+. The {110} Na reflections are distinctly absent from the XRD patterns of PGC sodiated down to 0.001 V, indicating that Na metal pore filling is not significant for pseudographitic carbons. The battery delivers highly promising Ragone chart characteristics, for example yielding 203 and 50 Wh kg-1 at 70 and 14000 W kg-1 (by total material mass in anode and cathode).
5:45 PM - ES2.5.08
Three-Dimensional Se/Bicontinuous Porous Carbon (BPC) Electrodes with High Energy Density and Stable Long Term Cycling Performances
Junjie Wang 1 , Subing Qu 1 , Runyu Zhang 1 , Ke Yang 1 , Shiyan Zhang 1 , Jagjit Nanda 2 , Paul Braun 1
1 , University of Illinois at Urbana-Champaign, Urbana, Illinois, United States, 2 , Oak Ridge National Lab, Oak Ridge, Tennessee, United States
Show AbstractAlthough intensive work has been conducted to improve the cycling stability and mitigate the capacity decay of Li-S battery electrodes, the development of Li-S batteries is still impeded by the “shuttle effect”. To date, the strategy of physically confining S within small micropores or chemically binding polysulfides with mediators did not resolve the issue fundamentally. Recently Se has been studied as alternative promising cathode material with similar performance to S. An additional benefit of Se is it undergoes solid state reactions with Li ions, directly converting to Li2Se without going through polyselenide intermediates in conventional carbonate electrolytes. As a result no “shuttle effect” is expected. However, confinement of Se in microporous carbon was still widely used in reported work, even though the volume expansion of Se is much larger than that of S. Here, a bicontinuous porous carbon (~50 μm) current collector was used to better accommodate the volume expansion of Se upon lithiation. And instead of the melt-diffusion loading method, a pulsed-voltage electrodeposition technique which was simpler and more controllable was applied to coat Se nanoparticles uniformly on surface of the porous carbon. Even without intentionally confinement or chemical treatment on carbon current collector, the 3D Se electrode showed capacities (660 mA h g-1 at 0.1 C) approaching theoretical value when cycled in carbonate electrolyte, indicating absence of “shuttle effect”. Moreover a stable cycling performance (500 cycles at 1 C) was achieved with VC added in electrolyte, thus delivering an electrode-based gravimetric energy density of 486 Wh L-1, which is higher than commercial LCO cathode (381 Wh L-1). The bicontinuous electrode structure which could provide fast pathways for both ions and electrons and the void space within electrode which could accommodate volume expansion of Se upon lithiation both contribute to the superior electrochemical properties of the 3D Se electrode.
ES2.6: Poster Session I
Session Chairs
Mauro Pasta
Yuan Yang
Jia Zhu
Thursday AM, April 20, 2017
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - ES2.6.01
A Mechanism of Deterioration in Cycling Performance of LiB Cells Using the SiO as Active Material
Takakazu Hirose 1 2 , Masanori Morishita 2
1 , Shin-Etsu Chemical Co., Ltd, Annaka-shi Japan, 2 , Yamagata University, Yonezawa Japan
Show AbstractTargeting to improve the cycling performance of the LiB using the SiO-C as the active anode material, its phase and structural changes in the SiO-C happened following to charge/discharge and the electron state of Si and Li was investigated in detail by the XAFS (x-ray absorption fine structure) focusing on Si K-edge and Solid state NMR (Nuclear Magnetic Resonance) analysis. Outcomes suggested that Si4+ absorbs Li then being changed to Li4SiO4 and partially changed to the silicon oxide in 2+～4+-oxidation state including Li silicate during first charging process, then SiO in 0+～2+-oxidation state including Li silicate was formed following to further charging and eventually all phases SiO compound in +0～+4-oxidation state including Li silicate existed at fully charged state. Also the results suggested that Li was released mainly from SiO compound in 2+-oxidation state at lower electric potential, roughly 0.7V vs Li/Li+ as the border, and Li4SiO4 released Li slightly at higher potential and to generate Si0+ during first discharging process. Li4SiO4 which contributed for releasing Li at the first discharging changed to the state of much less Li releasing and it was well regulated during cycles.
Such states like less Li releasing or stable condition was remained till 200 cycles at least. However confirmed that it became unstable after 419 cycles resulting it easily released Li. SiO compound which is constituted of Si1+~Si3+ has a certain reversibility in Li releasing and absorbing. And it stood at higher oxidized position than Si2+ following to cycles, actually it meant dispropotination was proceeding. La-APT (Laser-assisted atom probe tomography) was used to see the dispropotionation visually. In the area(Voxel Size of 0.5nm, 0.5nm, 0.5nm), successfully the figure which was constituted of Si with 40at% was observed. Following to cycles in other words following to dispropotionation, Si dots in the material were connected each other and its area became bigger. It suggested that the dispropotionation divided the material into Si (Si0+) and Li4SiO4(Si4+). Also it suggested that Si (Si0+) was changed to the ordinality of a long-cycle atom from the ordinality of a short-cycle atom in atomic level. To now, in general it is said that SiO-C is changing to Li silicide (Si0+) and Li silicate (Si4+) actually represented by Li4SiO4, and commonly believed that Li silicide is reversible capacity and Li silicate is not. However some results in this investigation suggested that Si4+ can be changed to lower oxidized SiOx(0≦x<2) even partially and it can release and absorb Li. At the end, following to those findings, a cell was designed with using lower potential below 0.7 V vs Li/Li+ and did performance check. The results was quite positive showing high stability of Li4SiO4 and SiO+ and other lower oxidized SiOx can contribute for releasing/absorbing Li continuously.
9:00 PM - ES2.6.02
All-Nanowire Based Anodes for Ultrafast Charge-Discharge Lithium Ion Batteries
Zhenxing Yin 1 , Jeeyoung Yoo 1 , Youn Sang Kim 1 2
1 Graduate School of Convergence Science and Technology, Seoul National University, Seoul Korea (the Republic of), 2 , Advanced Institute of Convergence Technology, Suwon Korea (the Republic of)
Show AbstractLithium-ion battery (LIB) is one of the most promising energy storage devices, due to their high energy density, high power density, stable long-term performance and good rate capability. With the growth in demand of electronic devices and electric vehicles, the ultrafast recharge-able LIBs have been widely researched. Recently, the one-dimensional conductive nanomaterials for current collectors and active materials have attracted considerable attention to improve the electrochemical performance of LIBs, which provide remarkable pathways for electrons transport and high surface area for ion diffusion.
Herein, we reported a new type of all-nanowire based anode for LIB cells with copper nanowire (Cu NW) as the current collector and multi-walled carbon nanotube (MWCNT) as the active material, respectively. The solution-processed Cu NWs and MWCNT present significant advantages to be applied as anode for LIBs, due to their excellent electrical conductivity, high aspect ratio and large surface area. The advanced anode of Cu NWs-MWCNT composites were fabricated by simple filtration method without any binder and conductive materials. As a free-standing structure, the Cu NWs-MWCNT composites film showed low sheet resistance and excellent flexibility with high porosity. In addition, the randomly Cu NWs structures as a highly conductive framework were closely connected with MWCNTs, resulting in improvement of the battery performances. The electrochemical half-cells were examined by cyclic voltammetry (CV), AC impedance and galvanostatic charge-discharge measurements, which assembled by Cu NWs-MWCNT composites electrode, PP separator, LiPF6 electrolyte and Li metal. The charge transfer resistance and bulk resistance were reduced with increment of the Cu NWs ratio. Furthermore, the Cu NWs-MWCNT composites anode for LIBs exhibited a high reversible capacity and improved capacity retention (465 mAh g-1 at 0.2 C) with a high columbic efficiency (about 100%) even high C-rate (215 mAh g-1 at 5 C). We believe that the suggested Cu NWs-MWCNT composites and their application for LIBs are promising in future electronic devices and electric vehicles.
9:00 PM - ES2.6.03
Study of Nanoporous Carbon Fabrics for Rechargeable Energy Storage Capacitors
Sergey Karabanov 1 , Andrey Karabanov 2 , Vladimir Litvinov 1
1 , Ryazan State Radio Engineering University, Ryazan Russian Federation, 2 , Helios Resource Ltd., Saransk Russian Federation
Show Abstract
One of the basic parts of electric double layer capacitors for rechargeable energy storage systems is the electrode material, the structure and properties of which define the capacity, operating voltage and discharge current.
The present paper examines a nanoporous material: carbon fabrics. The fabrics structure, impurities composition, the influence of impurity types on capacitor characteristics and the influence of thermal treatments on the impurities concentration are studied. The analysis of the capacitor equivalent circuit is made and the capacitor charge-discharge characteristics are investigated.
The carbon fabrics with electronic conductivity and the surface area of up to 2000 m2/g is used for the study. Aprotonic electrolyte was used as an electrolyte.
The impurities study was performed with the X-ray microanalysis method. The capacitor case was made of stainless steel.
The research results:
1. The investigated carbon material structure is characterized by availability of micro- and nonopores of different size: from a few nanometers to a few microns. Size distribution of pores is established.
2. The impurities content of carbon material and change of impurities content as the result of its thermal treatment in argon atmosphere is determined with the X-ray microanalysis method. Optimum temperature range for vacuum treatment is established.
3. The analysis of the capacitor equivalent scheme is carried out and its charge-discharge characteristics are investigated. The chosen equivalent circuit makes it possible to estimate the influence of pores different size on the capacitor charge-discharge characteristics. This is important for its application in real energy storage devices.
9:00 PM - ES2.6.04
Rational Design of Ultra-Durable Silicon-Based Anodes for High-Performance Lithium-Ion Batteries
Jaegeon Ryu 1 , Soojin Park 1
1 , Ulsan National Institute of Science and Technology, Ulsan Korea (the Republic of)
Show AbstractSilicon-based materials are key building blocks for next-generation lithium-ion batteries (LIBs) as replacing graphite anodes due to their highest gravimetric and volumetric capacity among various alloying materials. Nevertheless, huge volume change upon lithium ion uptake causes mechanical failure and continuous formation of solid-electrolyte-interphase (SEI) retarding the lithium ion kinetic. In this perspective, we employed multiple strategies, such as introducing multifunctional coating layers and realizing unique architecture prepared from inexpensive clay minerals, in isolation, which satisfies strict requirement for practical application. First, multifunctional layers composed of lithium silicate (Li2SiO3) and lithium titanate (Li4Ti5O12), provide structural robustness and effective lithium ion pathway for Si anode, which also enable to form a stable/uniform SEI layers significantly related to safety issue of batteries. Aside from this, feasible approaches for unconventionally structured Si materials are available through utilization of clay minerals. Depending on compositions, two types of novel structure, ultrathin nanosheet and hyperporous flake can be readily produced. They exhibited exceptional electrochemical properties (e.g., cycling stability over hundreds of cycles and durability toward high current density) along with successful accommodation of large volume change, rendering promising ultra-durable Si-based anodes.
9:00 PM - ES2.6.05
Chip Scale Carbon Nanotube Based Electrochemical Double Layer Capacitors with Ionic Liquid Electrolyte
Tyler Colling 1 2 , Stephan Turano 2 , W. Jud Ready 2 , Valerie Scott 3
1 , Georgia Institute of Technology, Atlanta, Georgia, United States, 2 , Georgia Tech Research Institute, Atlanta, Georgia, United States, 3 , NASA Jet Propulsion Laboratory, Pasadena, California, United States
Show AbstractPowerful energy storage devices are in high demand due to the many consumer electronics on the market. The decreasing size of these electronics has created a need for energy storage devices that are chip scale but still maintain a high energy storage capacity. Supercapacitors are devices that utilize unique charge storage mechanisms, such as a Helmholtz double layer (faradaic) or pseudocapacitance (non-faradaic), to achieve energy densities similar to batteries, and high power densities similar to capacitors. Through thoughtful optimization of the supercapacitor architecture by various functionalization steps, supercapacitors can be designed to efficiently utilize both charge storage mechanisms. The functionalization techniques used in this work are graphenation, the growth of graphene layers from the carbon nanotubes, and atomic layer deposition (ALD) of pseudocapacitive coatings such as TiO2 and TiNx. Previous results have shown a tremendous increase in gravimetric and volumetric energy density for supercapacitors featuring both graphenation and TiO2 with 1-butyl-3 methylimidazolium tetrafluoroborate electrolyte. The positive results from previous efforts suggest that there is a need for further optimization of the developed supercapacitors. A survey of pseudocapacitive coatings and ionic liquid electrolytes will be discussed.
9:00 PM - ES2.6.06
Structural Evolution of Si-Based Multicomponent for Li-Ion Battery Anodes
Dongki Hong 1 , Jaegeon Ryu 1 , Sunghee Shin 1 , Soojin Park 1
1 , Ulsan National Institute of Science and Technology, Ulsan Korea (the Republic of)
Show AbstractSi-based anode materials have been synthesized using various approaches to adapt great demands for more effective energy storage devices, specifically lithium-ion batteries (LIBs), in recent years because Si delivers high specific (~3579 mAh g-1 for Li15Si4 at room temperature) and volumetric capacities (~7000 mAh cm-3). However, dramatic volume expansion (>300% at fully lithiated state) occurs during lithium ion insertion/extraction and results in mechanical failure and pulverization of electrodes. These structural destruction and unstable surface are main issues for Si anodes which can directly influence on the electrochemical performances. Herein, the novel properties of Al2O3 are applied to Si particles through the selective etching and wet oxidation of commercial Al-Si alloy. When the etched Al-Si powders are wet oxidized, water vapor reacts with remained aluminium, thus forms Al2O3 layer on the outer surface of Si particles. As a result, we can expect to promote both structural and interfacial stability because thin Al2O3 layers have known as lithium ion conductor and electron insulator. The wet oxidized Al-Si alloy (ASWO) were tested in coin-type (R2032) cells and showed not only tremendous cycling performances of in both lithium half cell and full cell (natural graphite blended anode with LCO cathode), but also released the volume expansion of active materials.
9:00 PM - ES2.6.07
Aligned MWCNT Channels in Free Standing Polymer Nanocomposites for Li-Ion Battery
Balram Tripathi 1 2 , Pawan Kumar 1 , K B Sharma 2 , Rajesh Katiyar 1 , Ram Katiyar 1
1 Department of Physics, University of Puerto Rico, San Juan, Puerto Rico, United States, 2 Department of Physics, S S Jain Subodh PG (Autonomous) College, Jaipur, Rajasthan, India
Show AbstractThe investigation and development of flexible power sources has motivated to develop flexible, light weight, binder free and current collector free electrodes for Lithium ion batteries (LIBs). We therefore, report alignment and micro patterning of multiwall carbon nanotube (MWCNT) channels in a polystyrene matrix using magnetic field for lithium ion transport. In the presence of magnetic field, anisotropic MWCNTs rotate in the direction stabilized due to its magnetic susceptible nature. MWCNTs suspended in a liquid medium are trapped and they align into the direction of applied magnetic field. The alignment of MWCNT channels has been optimized by optical and Raman spectroscopy. The charge storage capacity and energy density has been found to be enhanced due to availability of aligned MWCNT channels and decreased weight of binder and current collector. Details of the observations will be discussed.
9:00 PM - ES2.6.08
Fabrication of Tube-in-Tube Nanostructure Carbon Materials for High-Performance Lithium-Sulfur Batteries
Luyi Chen 1 , Zhiwei Tang 1 , Weicong Mai 1 , Dingcai Wu 1 , Ruowen Fu 1
1 , Sun Yat Sen University, Guangzhou China
Show AbstractLithium sulfur (Li-S) batteries have been intensively researched recently due to their high theoretical capacity. However, several major issues have to be overcome before Li-S batteries can find their widespread practical applications. They include poor conductivity of sulphur and discharge product Li2S, serious dissolution of intermediate polysulphides with a shuttling phenomenon, and large volumetric expansion (76%) upon lithiation. To overcome these problems, many strategies have been developed to impregnate sulfur into porous materials to prevent the dissolution of intermediates and improve the conductivity of electrodes.
Low-dimensional nano-carbon structures, such as carbon nanotubes and graphene oxide, are able to sustain large lithium insertion/deinsertion strain. Especially, it is also believed that carbon nanotubes with highly conductive and short diffusion length could interact more efficiently with Li+ ions. Thus, it is necessary to design hybrid carbon materials which combine highly conductive carbon nano-materials with porous carbons to achieve high-performance sulfur-carbon electrode. Herein, we report a novel tube-in-tube nano-structured carbon material (TTNCM) as the host for sulfur cathode. The TTNCM materials were encapsulated into porous carbon materials through the following strategy: Firstly, MWCNT@SiO2@PS was initially prepared by grafting polystyrene (PS) chains from the surface of MWCNT@SiO2 via surface-initiated atom transfer radical polymerization (SI-ATRP). Then the MWCNT@SiO2@PS was treated through a facile hyper-crosslinking reaction to provide the PS shell with well-developed microporosity, thus forming porous hybrid nano-networks (MWCNT@SiO2@xPS). Finally the TTNCM was obtained after the carbonization treatment and removal of SiO2 from MWCNT@SiO2@xPS. This unique structure of as-prepared TTNCM can enhance the electrical conductivity, hamper the dissolution of lithium polysulfide, and provide large pore volume for sulfur impregnation. As a cathode material for Li-S batteries, the obtained S-TTNCM composite with sulfur delivered high reversible capacity, good cycling performance as well as excellent rate capabilities. At a current density of 2 C for 200 cycles, the discharge capacity of S-TTNCM is as high as 662mA g-1 (based on sulfur).
9:00 PM - ES2.6.09
Carbon Nanotube/MnO2 Hybrid Fiber Supercapacitor with High Areal Capacitance and Energy Density for Wearable Energy Storage
Changsoon Choi 1 , Kang Min Kim 1 , Seon Jeong Kim 1
1 Biomedical Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractResearch on improving performance of flexible and stretchable yarn or fiber-based supercapacitors for next generation wearable energy storage medium has become an important issue. Weavable hybrid yarn supercapacitors having high specific capacitance and energy density are demonstrated here because of high loadings of pseudocapacitance charge storage particles (above 90 wt% MnO2) are achieved by a novel biscrolling process. Novel biscrolled structure consists of trapped pseudocapacitive MnO2 nanoparticles within the helically scrolled carbon nanotube sheet and this enables short charge diffusion length, and high electrical conductivity. Despite the high loading of brittle metal oxide particles, the realized solid-state supercapacitors are flexible and can be made elastically stretchable. Due to the flexibility and stretchability, the hybrid fibers can be woven into commercial textile for wearable textile supercapacitor application. The maximum areal capacitances of the hybrid yarn electrodes, and the energy density of complete, solid-state supercapacitors were higher than previously reported wearable supercapacitors.
9:00 PM - ES2.6.11
Approach to Flexible Na-Ion Batteries with Exceptional Rate Capability and Long Lifespan Using Na2FeP2O7 Nanoparticles on Porous Carbon Cloth
Hee Jo Song 1 2 , Da-Sol Kim 2 , Jae-Chan Kim 2 , Seong-Hyeon Hong 1 , Dong-Wan Kim 2
1 Materials Science and Engineering, Seoul National University, Seoul Korea (the Republic of), 2 Civil, Environmental and Architectural Engineering, Korea University, Seoul Korea (the Republic of)
Show AbstractAs a post Li-ion batteries (LIBs), rechargeable Na-ion batteries (NIBs) are considered as one of the potential candidates for large-scale energy storage systems because of the abundance and low cost of sodium resources, and similar electrochemical behavior of Na-ion with the Li-ion for intercalation in the cathode. While there exist many challenges in the fabrication of cathodes, a polyanionic compound, Na2FeP2O7, has been in the spotlight as a potential cathode material in NIBs because of its rate capability, cyclability, and thermal stability. In this study, phase-pure Na2FeP2O7 nanoparticles (NFP-NPs) embedded in carbon were prepared via a citric acid-assisted sol-gel method, followed by a post heat treatment process. For the first time, NFP-NPs exhibit not only reversible capacity near the theoretical value (~97 mA h g-1) over the voltage range of 2.0–4.0 V (vs. Na/Na+). Moreover, they displayed superior rate capability of 77, 70, 66 and 65 mA h g-1 even at high rates of 10, 20, 30 and 60 C, respectively. Equally notable is the exceptional long-term cyclability at high rates. At the rate of 10 and 60 C, capacity retention at 5000 and 10000 cycles is 90.0 and 84.5%, respectively. In addition, NFP-NPs uniformly loaded on the surface of flexible porous carbon cloth (NFP-NPs@PCC) electrodes without any conductive agents and polymeric binders also exhibit excellent rate capability and long-term cyclability at high rate of 10 C (56 mA h g-1 after 2000 cycles). We show high-performance free-standing NFP-NPs@PCC electrodes for possible application in flexible NIBs.
9:00 PM - ES2.6.12
Synthesis and Characterization of High-Performance Energy Storage Materials for Supercapacitors
Bo Li 1 , Xiaomin Huang 1 , Limin Huang 1
1 , South University of Science and Technology of China, Shenzhen China
Show AbstractThe development and utilization of high-performance energy storage electrode materials meet the urgent need for high power and energy density devices. Here we report the synthesis and characterization of MnxOy/GO nanocomposites which show excellent electrochemical properties, via a one-step method that is a simple, quick, and uses a wide variety of cheap and nontoxic raw chemicals as a source and water as a solvent. When used as electrode materials for supercapacitors, the MnxOy/GO nanocomposites can deliver an outstanding specific capacitances of >1000F/g and 500 F/g at current densities of 0.1 A/g and 10 A/g, respectively with 2M KOH aqueous solution as electrolyte, which is twice as much as those reported in the literature. Also, the electrode materials show a good retention of 96.2% specific capacitance after 1000 cycles, and the energy density is 21.5 Wh/kg and the power density is 420 W/kg at 2 A/g, suggesting a promising potential application in high-performance electrochemical capacitors.
9:00 PM - ES2.6.13
Ultrathin Porous Co3O4 Nanosheets with Exposed {112} Facets as Anodes for Extraordinarily High Capacity Lithium-Ion Batteries
Renjie Wei 1 2 , Xianlong Zhou 3 , Tengfei Zhou 4 , Johnny Ho 1 , Juncheng Hu 2
1 , City University of Hong Kong, Hong Kong Hong Kong, 2 School of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan, Hubei, China, 3 , Nankai University, Tianjin China, 4 , University of Wollongong, Wollongong, New South Wales, Australia
Show AbstractVarious methodologies have been developed to obtain high-performance anodes for Li-ion batteries. Here, we report a simple and facile hydrothermal method followed by calcination to prepare ultrathin porous Co3O4 nanosheets. It is found that these nanosheets selectively expose their {112} facets as the main external surfaces. Importantly, a vast array of regular porous morphology is observed to form on these nanosheets with the adjacent two edges with a degree of 120°. When fabricated as anode materials for Li-ion batteries, the as-prepared Co3O4 nanosheets illustrate an extraordinarily high performance in terms of both capacity and stability.
9:00 PM - ES2.6.14
Phase Field Model of the Structural Evolution of Silicon Thin Films
Thanh Tran 1 , Eureka Pai 1 , Yue Qi 1
1 Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, United States
Show AbstractSilicon loses most of its capacity after some first cycles of using and the meso-scale phase evolution of Silicon anode impacts its capacity and rate-retention. To investigate this problem, a 2-D phase field model that tracks the exchange between lithiated and non-lithiated phases was developed. Starting with a random lithiated structure, multiple lithiation and delithiation cycles were simulated with idealized materials properties. The evolution of pores and morphology of lithiated phase distribution are tracked. Fast condensation is observed at the beginning cycles and then condensation speed abruptly reduces. This is because the phase separation happened fast near the edge of the Silicon nano ribbon. Pore collapsing has been observed experimentally. In experiments, these pores are filled with electrolyte and solid electrolyte interphase (SEI), which can be formed on the surface of the pores. Due to pore collapsing and Si thin film condensation, SEI will be trapped inside of Si and this reduces the overall lithium transported in the battery, thus resulting in capacity drop during time even without cycling after the anode is lithiated. Interestingly, experimental observed capacity fading rate was fast in the first few cycles and then abruptly become lower. This is consistent with the film condensation behavior we observe. In addition, the condensation of Lithium in Silicon is investigated in different rates and depths of charging. Generally, Lithium distribution becomes more coarsening at high rates and depths of charging. This is interpreted as Silicon losing capacity more at high rates and depths of charging. To further improve the model, the energy profile of LixSi and the concentration dependent diffusion coefficients predicted from first principles calculations are incorporated into the phase-field model.
9:00 PM - ES2.6.15
The Effect of Calendering Temperature for Sulfur Electrodes Used for Large-Scale Lithium-Ion Batteries
Rachel Ye 1 , Jeffrey Bell 1 , Kazi Ahmed 1 , Leon Peng 1 , Andrew Scott 1 , Daisy Patino 1 , Mihri Ozkan 1 , Cengiz Ozkan 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractCurrent commercial lithium ion batteries have reached their capacity limit due to the materials in use. To improve the capacity of lithium ion batteries, researchers have started to use new electrode materials such as sulfur and silicon. Sulfur, although being a high capacity cathode material, suffers from conductivity and expansion problems. To increase the conductivity of sulfur electrodes, a high percentage of carbon is usually added to the electrode, resulting in low sulfur loading. A common method to improve the conductive network and the sulfur loading of an electrode is to calendar or densify the electrode resulting in a more intimate contact between active material and conductive additive. Herein we look at the positive effects of calendaring sulfur electrodes at different temperatures. By elevating the electrode temperature, the heat softens the sulfur allowing the sulfur particles to better come into contact with the conductive additive and improving the conductive network. The improvement in the conductive network increases cycle life, capacity, and rate capability of the lithium-sulfur electrodes.
9:00 PM - ES2.6.16
Simple Synthesis of Carbon-Ni Nanowire Foam for Applications in Li-Ion Battery Anode
Chueh Liu 1 , Changling Li 1 , Mihri Ozkan 1 , Cengiz Ozkan 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractNovel current collector consisting of C-coated Ni nanowires is loaded with Si nanoparticles as Li-ion battery anode. Ni wires are synthesized by heating Ni(Ac)2 with glycerol at 400oC for 40 min. Ni nanowires are produced by oxalic acid etching of Ni wires followed by H2 reduction. Carbon coating on Ni nanowires is performed at relatively low temperature (350oC) with acetylene to improve electrical conductivity. Commercial Si nanoparticles mixed with polyacrylic acid binder are coated onto Ni nanowires attached on Ni foam (Si/Ni NWF) as the anode of Li-ion battery. The Si/Ni NWF anode can be cycled 750 times at C/2 with capacity ~ 300 mAh g-1 without extra carbon additive since the electrical conductivity is improved by the intimate contact between Si nanoparticles and C coated Ni nanowires. Superior stability is attributed to the void space accommodating volume expansion of Si nanoparticles.
9:00 PM - ES2.6.17
Nickel Oxide Nanowire Foam—The Effect of Various Nanowire Morphologies on Li-Ion Battery Performance
Yiran Yan 1 , Chueh Liu 1 , Changling Li 1 , Zafer Mutlu 1 , Cengiz Ozkan 1 , Mihri Ozkan 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractAn increasing demand of electric vehicles (EVs) as environmental friendly transportation has attracted great attention for studies about long-range and light weight batteries. Lithium-ion batteries (LIBs) are among the top heavily investigated with high capacity and great stability and low cost. Nickel oxide (NiO) remains a promising anode material due to its high theoretic capacity (718 mAh/g) and low manufacturing cost. A NiO nano-sized framework has been fabricated to accommodate these common challenges of LIBs: high capacity, stable cycling and high energy density. Here, we utilized commercial available nickel foam as template for nickel nanowires (Ni NWs) (30-150 nm diameter) synthesis by heating nickel acetate and glycerol. Different morphology of nickel oxalate nanoneedles were fabricated using oxalate acid at different water contents. The nanoneedles were further reduced to Ni NWs by hydrogen at high temperature and later annealed to NiO NWs. Different morphologies of NiO NWs on Ni foam backbone revealed different porosity and surface area and had great impact on battery performance. Batteries showed capacity of 680 mAh/g after 1000 cycles at 0.5 C. The study indicated controllable size and morphology of NiO NWs and improved performance via surface area and porosity enhancement.
9:00 PM - ES2.6.18
In Situ Synthesis Graphene/CuO Composite for Anode of Li-Ion Battery
Jeeyoung Yoo 1 , Sanghun Cho 1 , Zhenxing Yin 1 , Youn Sang Kim 1 2
1 , Seoul National University, Seoul Korea (the Republic of), 2 , Advanced Institutes of Convergence Technology, Suwon Korea (the Republic of)
Show AbstractThe remarkable development of IT devices give rise to dramatic progress of lithium ion batteries (LIBs) technology during past decades. LIBs are applied various equipment from small electronic devices like mobile phone to large scale system like energy storage system. Recently, LIBs researches are focused on high energy density and cycle stability depending on growing demand of energy storage system and electric vehicles. To achieve high energy density, electrodes have to adopt high capacity materials. In cathode parts, Li excess layered oxide, Ni rich layered oxide have been investigated and some cases are commercialized. In addition, various anode materials which have high theoretical capacity have been proposed to enhance energy density. Most of high capacity materials can be summarized of two type. The one is metal and metal oxide which have different lithiation mechanisms (alloying, conversion), and representative material is silicon. The other is nano structured carbons like CNT or graphene. In case of materials lithated alloying or conversion reaction, shows extremely unstable cycle stability, which caused by volume expansion. So, in many case of adopting metal or metal oxide, carbonaceous materials are applied together. Nano structured carbon have complex manufacturing process using of strong acid and long processing time. Consequently, new anode materials are required for advanced stability and high capacity LIBs.
Herein, we introduce in-situ synthesis of graphene and CuO with Cu ion ink. To make graphene, we apply decomposition process of Cu ion ink to graphite. Decomposition of Cu ion ink makes the expanded layer spacing of graphite, because process of decomposition produces the hydrogen (H2) and carbon dioxide (CO2), which is widely utilized to graphene exfoliation gas. And additional product of Cu ion ink decomposition is CuO. CuO is valuable anode materials by conversion reaction. The proposed graphene/CuO composite has been prepared with simple mix and baking process. The homogeneous mixture of graphite and Cu ion ink are sintered at 350 oC for 8h. During sintering Cu ion ink decomposition process occurred, and then graphene/CuO composite was obtained. The structure of graphene/CuO composite is confirmed by XRD, TEM and Raman spectrum. The graphene/CuO composite applied as anode of LIBs. Through cyclic voltammetry, CuO redox peaks were observed at 0.8V, 1.5 V, 2.1 V and 2.5V. The galvanostatic charge-discharge test and capacity retention test exhibit the enhanced capacity of 552.67 mAh/g at 0.2C. In addition, the ratio control of Cu ion ink and graphite results show proportional capacity increasing and layer expansion phenomenon. These results describe that prepared anode form the graphene/CuO composite is suitable for high capacity and long cycle stability of LIBs performance. In conclusion, we believe that the proposed hybrid anode is a promising anode for LIBs and it applies future electric vehicle and energy storage system.
9:00 PM - ES2.6.19
Nanostructured MoO2 as an Anode Material for Lithium Ion Storage Site in Lithium-Ion Batteries
Hojae Jung 1 , Ayoung Kim 1 , Eunjun Park 1 , Hansu Kim 1
1 Energy Engineering, Hanyang University, Seoul Korea (the Republic of)
Show AbstractMoO2 has been considered as a promising anode material for lithium secondary battery due to its higher theoretical capacity (209 mAhg-1). However, previous studies showed that MoO2 has poor cycle performance caused by phase transition from monoclinic to orthorhombic phase during lithium intercalation and de-intercalation. In this work, nanostructured MoO2 were prepared by simple solid state synthesis and investigated as an anode material for lithium rechargeable battery. Nanostructured MoO2 showed highly stable capacity retention as high as 84% of the initial capacity after 100 cycles, indicating highly stable lithium ion insertion and extraction into MoO2 lattice. In the presentation, more detailed electrochemical performances of MoO2 and ex-situ XRD analysis of lithium intercalated MoO2 anode will be discussed.
9:00 PM - ES2.6.20
Three-Dimensional Pore-Patterned Carbon Structures for Their Energy Storage Application
Cheolho Kim 1 , Jun Hyuk Moon 1
1 , Sogang University, Seoul Korea (the Republic of)
Show AbstractCarbonaceous materials have been attracted in electrode materials for energy storage devices. We demonstrate multi-beam interference lithography to fabricate 3D sub-micrometer pore-patterned thin films of photoresists, and a direct carbonization of the pattern to produce the pore-patterned carbon. The pore-patterned carbon was characterized by scanning electron microscope and transmission electron microscopy. The properties of obtained amorphous carbon material were analyzed by Raman spectroscopy. And, the elemental composition of 3D pore-patterned carbon was quantified by XPS measurements. Also, the electrochemical performances were analyzed with the results of cyclic voltammetry, galvanostatic charge/discharge and cycle performance.
9:00 PM - ES2.6.21
Anodized Porous Oxide Thin Films for Energy Application
Hua Cheng 1 , De Hui Zhang 1 , Dong Wu 1 , Zhouguang Lu 1
1 Department of Materials Science & Engineering, South University of Science and Technology of China, Shen Zhen, Guang Dong, China
Show AbstractHighly ordered porous oxide thin films including Fe3O4, NiO, ZnO, CuO, Co3O4 have been prepared by a facile multi-pulse electrochemical anodization method. The as-obtained oxide films are directly grown on the corresponding metallic substrate, featuring nano-channels with periodically rugated channel walls running throughout the film thickness direction and can also be peeled off from the substrate to become free-standing. The geometry and size of the films can be finely tuned by the electrochemical anodization parameters. The fabricated oxide films have been intensively applied as electrode materials for lithium ion batteries and micro-combustion. Very promising performance has been achieved due to the very special periodic rugated nanostructures of these anodized thin films.
9:00 PM - ES2.6.22
Titanium Dioxide Coated Graphite Anode Material for Enhancement of High Rate Capability Lithium-Ion Battery
Dong Jae Chung 1 , Dae Sik Kim 1 , Hansu Kim 1
1 , Hanyang University, Seoul, SE, Korea (the Republic of)
Show AbstractLithium ion Battery (LIB), one of the most promising solutions for electric vehicles, has faced several technical issue including high energy density, ultimate safety and fast charging capability. Commercial graphite material, used as anode materials for LIB, has prominent limitation in term of high rate capability. To overcome this limitation, various materials have been investigated as an alternative to replace commercialized graphite material. In this work, titanium dioxide coated graphite were investigated as an anode material for enhancing fast charging capability of LIB. Without any sacrifice of reversible capacity and long term cycle performance, titanium dioxide coated graphite anode electrode showed an outstanding rate capability of 96.4 % of the capacity retention at a rate of 3.6 A g-1 compare to that tested at a rate of 72 mA g-1. In the presentation, the electrochemical performance and physical/chemical properties of the titanium dioxide coated graphite will be discussed in more detail.
9:00 PM - ES2.6.23
Fe2O3 Anode Material for Na-Ion Rechargeable Batteries
Riccardo Ruffo 2 , Gianluca Longoni 2 , Patrizia Frontera 1 , Fabiola Panto 3 , Sara Stelitano 4 , Salvatore Patane 5 , Pier Antonucci 1 , Saveria Santangelo 1
2 , Milano Bicocca University, DSM, Milano Italy, 1 , Mediterranea University, DICEAM, Reggio Calabria Italy, 3 , Mediterranea University, DIIES, Reggio Calabria Italy, 4 , Università della Calabria, DF, Arcavacata di Rende Italy, 5 , Messina University, MIFT, Messina Italy
Show AbstractLi-ion batteries play a predominant role in the market of power sources for cordless devices with a production higher than 100 million cells/month and about 1500 ton/month of electrode materials. These figures may increase in the future due to the use of LIBs in automotive applications, with consequent increase of the Li raw material (Li2CO3) consumption. Nowadays, the availability of Li2CO3 is restricted to few countries and lithium may become a strategic material in the near future with the booming of its cost and the raising of geopolitical issues. For this reasons Na-ion batteries (SIBs) are getting increasing attention thanks to the higher availability of Na sources and the possibility to drive down the energetic demand connected to raw materials extraction and processing. However, the development of the SIB technology requires the discovery and the investigation of new electrode materials with reversible Na+ intercalation reaction.
This contribution deals with preparation, characterization and testing as negative material in SIBs of nanostructured hematite (Fe2O3) based electrodes. The high theoretical specific capacity (1007 mAhg−1), the environmental compatibility and the wide availability of raw materials were the reasons for the choice.
Fe2O3 powders, prepared by electrospinning, consist of fibers (~5 mm in length and ~300 nm in diameter) with a coral-like structure, resulting from the interconnection of round-shaped polycrystalline grains.
Fe2O3-based electrodes were cycled in half cells using metallic sodium as counter and reference electrode in the 3.00−0.01 V vs. Na+/Na potential range. The potential/charge profiles obtained in a pure Fe2O3 electrode in quasi-equilibrium conditions showed a reversible capacity of 700 mAhg−1, high first-cycle Coulomb efficiency and an average voltage around 1.0 V vs. Na+/Na.
To demonstrate the potential application in SIBs, Fe2O3/carbon composite electrodes were cycled at 6 different current rates ranging from 50 mAg−1 to 2 Ag−1. At the lowest current density, the electrodes were able to deliver a reversible specific capacity of 500 mAhg−1, which decreased to 100 mAhg−1 at the highest rate. After 70 cycles, the material showed 70% of capacity retention with a Coulomb efficiency close to 100%.
The sodiation/desodiation reaction mechanism and the morphological evolution will be discussed on the basis of ex-situ SEM, XRD and Raman measurements performed on pristine and cycled electrodes.
9:00 PM - ES2.6.24
Hydrothermal Synthesis of LiFePO4 Cathode-Active Material Using Iron Metal
Satish Bolloju 1 , Rupesh Rohan 1 , Shao-Tzu Wu 1 , Ho-Xin Yen 1 , Yuya A Lin 1 , Jyh-Tsung Lee 1
1 , National Sun Yat-Sen University, Kaohsiung City Taiwan
Show AbstractGreenness and cost effectiveness are important aspects to be considered for the synthesis of a material. LiFePO4 has attracted huge attention as a promising cathode material for lithium-ion batteries in the last few decades. In the present work, LiFePO4 has been hydrothermally synthesized using iron metal (Fe0) as an iron source. Fe0 delivers 100% atomic efficiency, theoretically, and eventually incorporates greenness to the method. In addition, Fe0 also acts as an in-situ reducing agent, which makes the approach inexpensive further. Phase evolution of the LiFePO4 material is studied by powder X-ray diffraction (XRD) at different temperatures and a plausible mechanism is proposed. Phase purity of the calcined LiFePO4 material is confirmed from the XRD pattern. Rietveld refinement is performed on the XRD pattern of the calcined LiFePO4 material and its unit cell parameters are found to be a = 10.3170 Å, b = 5.9992 Å, c = 4.6900 Å. The scanning microscope images depict that the synthesized LiFePO4 particles are micrometer-sized. While cyclic voltammetry studies reveal good reversibility of the batteries assembled with the synthesized LiFePO4, the corresponding discharge capacity is found to be 165 mAh g-1 at 0.1 C-rate with a good cycle life at 0.5 C-rate, which is comparable to the conventionally synthesized LiFePO4 materials.
9:00 PM - ES2.6.25
N-Doped Hierarchical Mesoporous Carbon Tubes for High Performance Supercapacitors
Wen Zhang 1 , Honglu Wu 1 , Jingyue Liu 1
1 Department of Physics, Arizona State University, Tempe, Arizona, United States
Show AbstractThe increasing demand for portable electronic devices and environmentally clean electric vehicles requires the development of high performance energy storage systems. Supercapacitors have received increasing attention because of their high power density, fast recharge capability and long cycle life. Hierarchical carbon nanoarchitectures are strongly desirable for developing the next generation supercapacitors or long-lasting batteries [1-2]. We recently developed a novel synthesis approach, via catalytic reactions, to produce three-dimensionally patterned growth of N-doped hollow carbon arrays (N-HCA) on carbon fibers (N-HCA@CFs). The facile synthesis protocol is repeatable, scalable and easy to process. The N-HCA@CFs can be directly used as integrated electrodes for supercapacitors and exhibited a high specific capacitance of 240 F/g at 20 A/g in 6 M KOH aqueous solution in three-electrode mode. The specific capacitance still maintained a value > 190 F/g even when the current density was increased to 80 A/g. These excellent electrochemical performances were attributed to the novel design and synthesis of the porous vertical N-HCAs which provide both enhanced electronic and ionic transport. Compared to the non-doped HCA@CFs supercapacitors, the N-doping significantly enhanced the performance of the designed supercapacitors. The N-HCA@CFs electrodes are expected to provide new opportunities for carbon-based materials to power flexible electronic devices. The design strategy, the synthesis and N-doping processes of the HCA@CFs electrodes, and the electrochemical properties of the N-HCA@CFs will be discussed [3].
1. Simon, P.; Gogotsi, Y. Nature Materials 7 (2008): 845-854.
2. Pech, D. et al. Nature nanotechnology 5 (2010): 651-654.
3. Zhang, G. et al. Advanced Functional Materials 26 (2016): 3012-3020.
4. This research was funded by the College of Liberal Arts and Sciences of Arizona State University. H. Wu acknowledges the financial support from the China Scholarship Council. The authors gratefully acknowledge the use of facilities within the LeRoy Eyring Center for Solid State Science at Arizona State University.
9:00 PM - ES2.6.26
Development of Tin Based ALD Anodes for 3D Thin Film Lithium Ion Batteries
Thomas Schmitt 1 , Alexander Pearse 1 , Keith Gregorczyk 1 , Nam Kim 1 , Chanyuan Liu 1 , Sang Bok Lee 1 , Gary Rubloff 1 , David Stewart 1
1 , University of Maryland College Park, College Park, Maryland, United States
Show AbstractDesigning nanoscale energy storage devices requires high capacity anode materials that can be deposited in a controlled manner conformally over architectures with extreme tortuosity and/or ultrahigh aspect ratios to be competitive with current technologies. Atomic layer deposition (ALD), which uses a combination of metal-organic and oxidant precursors, is a technique that meets these requirements. ALD provides capabilities of growing devices sequentially over a large variety of 3D geometries including fibers, trenches, pillars, and pores. Furthermore, in recent years, ALD has been used to explore a variety of applications in energy storage including the development of cathode and anode materials, creating nanoscale artficial SEIs, and even solid-state electrolytes such as LiPON. This work aims to further that exploration by examing the tin oxynitride system where the composition of the material can be finely tuned through choice and dose of a particular precusor. This system is interesting as an anode due to its conversion reaction with lithium ions which leads to high energy density and long cycling stability.
Tin oxide (SnO2), tin nitride (SnN), and tin oxynitride (SnOxNy) are potential anode materials capable of being deposited by ALD and the latter two remain largely unexplored from both a process and electrochemical perspective. Here we develop ALD processes for SnO2, SnN, and SnOxNy and compare the results. These processes use tetrakis(dimethylamino)tin(IV) (TDMA-Sn) as the metal-organic precursor and we explore a variety of potential oxidants such as O2, O3, H2O, O2 plasma, and N2 plasma. Here we report all process parameters including growth rate per cycle as a function of dose and temperature. The properties of these materials are explored through a novel integrated deposition, x-ray photoelectron spectroscopy, and Ar-glove box system such that samples can be prepared, characterized, and electrochemically tested without exposure to air. We show that by choosing the appropriate precusors and tuning the dose the material composition can be tuned from pure oxide to nearly pure nitride. The electrochemical performance of the produced materials is tested in standard liquid coin cells as well as through the fabrication of solid-state cells using a recently developed ALD process for Li2PO2N.
9:00 PM - ES2.6.27
Silicon-Tin-Carbon Nanocomposites—Rational Exploration of Processing Parameters
Nicole Wagner 1 , Jie Ma 2 , Lorenzo Mangolini 2
1 Industrial and Manufacturing Engineering, California State Polytechnic University, Pomona, Pomona, California, United States, 2 Mechanical Engineering, University of California, Riverside, Riverside, California, United States
Show AbstractWe have performed a detailed study of the processing-property relations for silicon-tin-carbon nanocomposite structures for lithium ion battery applications. While it is well-known that the performance of silicon anodes is improved by a carbon coating, recently it has been suggested that dispersing tin nanoparticles in the silicon network is highly beneficial to the overall device performance. While promising, this greatly expands the experimental parameter space so that a careful optimization effort is needed to fully leverage the potential properties of silicon-tin-carbon structures. In this study we have varied the size of the silicon particles in the 5-50 nm range, continuously varied the silicon-to-tin ratio, and precisely controlled the thickness of the carbon coating to map the importance of such parameters on the anode performance. We have in particular monitored the charge-discharge stability over several cycles and the first cycle coulombic efficiency. We have found that the addition of tin at a level of just a few percent points by weight greatly improves stability, although it is not sufficient alone to achieve an anode that is stable over few hundreds of cycles. The particle size also plays a crucial role in battery stability, with smaller particles improving the stability while being detrimental to the first cycle coulombic efficiency. In addition, we have found that the carbon coating greatly enhances the device stability when achieved via a CVD process using acetylene as precursor. Achieving a carbon coating by carbonizing a polymer precursor inevitably reduces the overall performance.
9:00 PM - ES2.6.28
Niobium Pentoxide Nanowire Electrochemical Fabrication for Energy Storage Applications
Gaurav Jha 1
1 , University of California, Irvine, Irvine, California, United States
Show AbstractNiobium Pentoxide has been investigated as pseudocapacitive material for energy storage due to its fast Li+ intercalation kinetics and high capacitance. It has been shown that the orthorhombic crystallographic orientations favor higher capacitance values than the amorphous form, and is obtained by annealing the material at high temperatures. In the present work, fabrication of Nb2O5 nanowires has been attempted, for the first time, using Lithographically Patterned Nanowire Electrodeposition (LPNE) technique. The nanowire morphology has been reported to enhance the access of Li+ based electrolyte to the bulk of the material and promote redox energy storage reactions. Electrodeposition of amorphous Nb2O5 nanowires has been described and subsequent heat treatment to obtain the required crystal structure is also demosntrated.
9:00 PM - ES2.6.29
Electrochemical Performance of TMD/KMnO4 Hybrids as Supercapacitor Electrode Materials
John Petrovick 2 1 , Gabrielle Biby 1 , Monsuru Abass 1 , Gurpreet Singh 1
2 Chemical Engineering, University of Massachusetts, Amherst, Massachusetts, United States, 1 Mechanical and Nuclear Engineering, Kansas State University, Manhattan, Kansas, United States
Show AbstractTransition metal dichalcogenide (TMD) nanosheets involving MoS2 and WS2 were interfaced with KMnO4 at high temperature in an attempt to improve the performance of TMDs as supercapacitor electrode materials. Morphology characterization was performed by use of scanning electron microscope (SEM), and the electrochemical performance was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) techniques. A mixture of 25 wt.% WS2/75 wt.% KMnO4 showed the best performance, with an areal capacitance of 66.30 mF cm-2. Future work would involve optimization of the processing temperature and testing as battery electrode material.
9:00 PM - ES2.6.30
Spontaneous Exfoliation of Transition Metal Dichalcogenide Crystals and Performance as Electrodes for Rechargeable Batteries and Supercapacitors
Monsuru Abass 1 , Lamuel David 1 , Gurpreet Singh 1
1 Mechanical and Nuclear Engineering, Kansas State University, Manhattan, Kansas, United States
Show AbstractHere we study superacid assisted exfoliation and sodium cycling behavior of Transition Metal Dichalcogenide (TMD) electrodes as potential high capacity materials for metal-ion batteries and supercapacitor electrodes. We show that sodium capacity and cycling efficiency for freestanding TMD electrodes (~250 mAh g-1) is higher than graphite (~35 mAh g-1) and graphene oxide (~75 mAh g-1) electrodes reported so far. Our results also highlight the challenges associated with capacity decay and voltage hysteresis in TMDs, which become evident after only a few initial cycles.
9:00 PM - ES2.6.31
Synthesis of MnO2 Nanoflakes-Coated CNT Particle for Energy Storage Application
Donghee Gueon 1 , Jun Hyuk Moon 1
1 , Sogang University, Seoul Korea (the Republic of)
Show AbstractDevelopment of energy storage applications is the most critical issues in both academia and industry due to the various demands such as portable devices and electric vehicles. As a result, high energy electrode material with long cycle life and high power density need to be developed. To ensure these requirements, we introduce synthesis of MnO2 nanoflakes on CNT particle surface for high-electrochemical performance supercapacitors. The CNT particles synthesized by drying the CNT-dispersed aerosol produces a intertwined CNT assembly by capillary force, and the subsequent growth of MnO2 on the CNT surface produces high surface area MnO2 nanoflake shell. We control the amount of MnO2 decoration on the CNT particles and obtain a specific capacitance of 370 F/g. This capacitance is 14 times higher than that of bare CNT particles. These high electrochemical performance is attributed to the contribution of the high pseudocapacitance of a compact MnO2 nanoflake and the high electrical conductivity of CNT particles with dense packing. Our design of highly dense CNTs and a core-shell morphology creates new opportunities for high performance energy storage devices.
9:00 PM - ES2.6.32
Anion Redox Driven Electroreduction Synthesis of Silicon Nanowire in Molten Salts at Low Temperature as High Capacity Lithium-Ion Battery Anode
Yifan Dong 1 2 , Liqiang Mai 2 , Song Jin 1
1 Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States, 2 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei, China
Show AbstractSilicon is an extremely important technological material and potential high capacity anode material for lithium-ion battery, but producing silicon from silicon dioxide/silicates consumes a lot of energy and generates much CO2. Herein, we developed a new, environmentally friendly method to produce silicon nanowires in application for lithium storage at unprecedented low temperature. The cheap, sustainable silicon precursors (CaSiO3) is used as silicon source and can be obtained from terrestrial rocks to enable the sustainable production of silicon nanowires via anion redox electroreduction synthesis in molten salts. The addition of CaO in the melt clearly increases the current densities as well as the reaction rates. This is as a result of CaO which would ionize to create more O2- in the melt and is likely to increase the migration rate for O2- ions in the melt. The low temperature is achieved by introducing ternary molten salt system. CaSiO3 can be dissolved in the melt and then electrochemically reduced to Si in a molten salt. We also investigate the application of the electrochemically produced Si nanowires as the anode materials in Li-ion batteries. Compared with bulk Si, the as-prepared Si nanowire possesses facile strain relaxation, allowing them to increase in diameter and length without breaking and allows for efficient 1D electron transport down the length of every nanowire. Thus, Si nanowire yielded the high capacity of 2310.3 mAh g-1 at a current density of C/40 and is able to retain a capacity of 875 mAh g-1 after 500 cycles at C/2. We believe that our strategy towards lowering melting temperature and increasing yield can be further applied in other molten salt systems and our process can be further expanded in to other systems such as in waste glass refinement.
9:00 PM - ES2.6.33
Effects of Doping with Transition Metal (Fe or Cu) on Electrochemical Performance for Li-Rich Cathode Material
Sung Nam Lim 1 , Shin Ae Song 1 , Ki Young Kim 1
1 , Korea Institute of Industrial Technology, Ansan Korea (the Republic of)
Show AbstractThe lithium ion batteries have been globally studied concurrently with the interest in Hybrid Electric Vehicles (HEV) and Electric Vehicles (EVs), because of global warming and exhaustion of fossil fuel. The Li-rich, Li1+xMxO2(0250 mAh g-1). However, they still were hard to use as commercial cathode material, because their poor rate capability and inferior cycle performance caused from low electronic conductivity and phase transformation as their intrinsic property remains an unsolved drawback. Especially, the capacity fading could be related to the inferior structure stability of Li2MnO3 component, which is likely to transform from layered structure to spinel-like structure during cycle. To solve their drawback, many groups have been tried to trace doping to prevent phase transformation or incrase electrical conductivity by using transition metal such as Cr, Ru, Zn and Al.
In this study, we prepared Fe- or Cu-doped Li-rich cathode materials, formulated as Li1.167Mn0.548-xMx Ni0.18Co0.105O2 (M = Fe or Cu), by using spray pyrolysis to investigate the effect of Fe or Cu ion doping on their rate capability and cycle performance, respectively. And we investigated the effect of each dopant on physical properties such as structure, morphology and surface area of Li-rich cathode material.
9:00 PM - ES2.6.34
Electrochemical Properties of Si/SiOx-Conductive Polymer Core-Shell Nanospheres as a High Capacity Anode Material for Lithium-Ion Battery
Eunjun Park 1 , Jeonghun Kim 2 , Dong Jae Chung 1 , Min-Sik Park 3 , Jung Ho Kim 2 , Hansu Kim 1
1 Department of Energy Engineering, Hanyang University, Seoul, SE, Korea (the Republic of), 2 Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, North Wollongong, New South Wales, Australia, 3 Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Suwon Korea (the Republic of)
Show AbstractNon-stoichiometric SiOx based materials have gained much attention due to its stable cycling performance as high capacity anode materials for lithium-ion batteries. However, the electrode materials have been still limited to commercial use because of its high-cost process and insufficient electrical conductivity. In this work, the conductive polymer, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS), was introduced as a flexible coating material on the surface of Si/SiOx nanospheres to improve electrochemical performance for lithium-ion batteries. To prepare these materials, simple and cost-effective route using a solution process-based approach was employed. As-prepared core-shell structured materials with the small amount (1wt. %) of PEDOT:PSS showed a reversible capacity of 968.2 mAh g-1 with superior long-term cycling performance over 200 cycles even at a current density of 1C (1000 mA g-1). The robust and electroconductive shell structure would be assisted to improved electrochemical performance of Si/SiOx nanospheres. The microstructure and electrochemical properties of the Si/SiOx-conductive polymer core-shell nanospheres will be discussed in more detail.
9:00 PM - ES2.6.35
Characterizations of Al2O3 Coatings on Lithium-Ion Cathodes—Effects of Cathode Compositions and Annealing Temperatures
Binghong Han 1 , Cameron Peebles 1 , Tadas Paulauskas 2 , John Vaughey 1 , Fulya Dogan Key 1
1 , Argonne National Laboratory, Cambridge, Massachusetts, United States, 2 Department of Physics, University of Illinois at Chicago, Chicago, Illinois, United States
Show AbstractAl2O3 coatings on cathode materials are thought to be an effective way to prevent chemical and structural evolutions during battery operation and therefore to improve the cyclability of lithium-ion batteries. However, the systematic study on the effect of coating process and cathode composition on interfacial morphology and composition and their effect on electrochemical performance is missing. In this work, we used a wet-chemical method to synthesize a series of Al2O3-coated LiNixCoyMn1-x-yO2 (NCM) with different post sintering conditions. Using nuclear magnetic resonance and electron microscopy we have shown that the homogeneity, morphology and atomic structures of the coating layers are highly depended on the post heating temperature, and schemes of surface coating layer evolution are built upon a comprehensive study on aluminum local order, coating-bulk interactions and imaging characterizations. The chemical composition of cathode materials also demonstrates big influence to the surface morphology evolution as well as the electrochemical performance of the Al2O3-coated NCM materials, which could be due to the different energy penalty for Al intercalation from surface coating layer into the cathode bulk.
9:00 PM - ES2.6.36
Metal Oxide Protected Lithium Anode Enabled by Atomic Layer Deposition towards Practical Applications
Lin Chen 1 2 3 , Justin Connell 3 , Anmin Nie 4 , Zhennan Huang 5 , Kevin Zavadil 6 , Kyle Klavetter 6 , Reza Shahbazian-Yassar 5 , Jeffrey Elam 2 3
1 , Illinois Institute of Technology, Chicago, Illinois, United States, 2 , Argonne National Laboratory, Lemont, Illinois, United States, 3 , Joint Center for Energy Storage Research, Lemont, Illinois, United States, 4 , Shanghai University, Shanghai China, 5 , University of Illinois at Chicago, Chicago, Illinois, United States, 6 , Sandia National Laboratory, Albuquerque, New Mexico, United States
Show AbstractLithium metal is considered to be the “holy grail” of battery anodes due to its ultrahigh theoretical capacity (3,860 mAh/g), low potential (-3.04 V versus standard hydrogen electrode), and very low density (0.534 g/cm3). However, dendrite growth during cycling and low Coulombic efficiency, resulting in safety hazards and fast battery fading, are significant technical hurdles that prevent the commercialization of lithium metal anodes. In this work, we used atomic layer deposition to grow conformal, ultrathin Al2O3 films on lithium metal in an effort to mitigate these technical problems. We employed in-situ QCM, for the first time, to study the growth mechanism of Al2O3 on lithium and found larger growth than expected during the initial cycles followed by steady growth at the expected rate. We discovered that both carbonate and ester electrolytes show enhanced wettability on Li with ALD coatings, leading to more uniform and dense SEI formation as well as enabling stable battery operation with smaller electrolyte volumes compared to the uncoated Li. Moreover, XPS investigations and in-situ TEM demonstrate excellent Li dendrite prevention with the robust ALD Al2O3 films. As a result, ALD protected Li provides several times longer cycling life with stable Coulombic efficiency and voltage profiles than bare Li at a practical current density of 1 mA/cm2.
9:00 PM - ES2.6.38
Enhanced Lithium and Sodium Storage of Red Phosphorus-Based P-TiP2 -C Nanocomposite Anode
Sang-Ok Kim 2 1 , Arumugam Manthiram 2
2 , University of Texas at Austin, Austin, Texas, United States, 1 , Korea Institute of Science and Technology, Seoul Korea (the Republic of)
Show AbstractTo meet the requirements of the rapid development of a wide range of large-scale energy storage systems, considerable efforts are being devoted to develop high-performance Li-ion batteries (LIBs) and Na-ion batteries (SIBs). Elemental phosphorus has attracted much attention in recent years as one of the most promising anode materials due to its high theoretical capacity of 2595 mA h g-1 for both LIBs and SIBs. However, its major drawbacks such as the large volume change (> 300%) upon Li- and Na-alloying reactions and low conductivity (10-14 S cm-1) lead to poor capacity retention and low rate capability. So far, while some progress has been made by making composites with carbonaceous materials that could enhance conductivity and serve to buffer the volume changes, the use of large amounts of carbon (> 30 wt. %) has resulted in low initial Coulombic efficiency and low tap density of the composites.
We present here a phosphorus-based composite with a non-carbonaceous reinforcing matrix. With the aid of the conductive TiP2 buffer, the P–TiP2–C composite shows a high reversible capacity of ~ 1116 mA h g-1 with a high initial Coulombic efficiency (CE) of 86%, outstanding cycling stability with > 87% capacity retention after 100 cycles, and good rate capability in LIBs. It also shows a high reversible capacity of ~ 755 mA h g-1 with a high initial CE of 80%, stable cyclability (> 80% capacity retention after 100 cycles), and good rate capability in SIBs. The performance improvement is attributed to the presence of in situ formed conductive TiP2 matrix that plays a crucial role in enhancing the electrochemical performance by providing high conductivity, structural stability, and an effective buffering to accommodate the volume change.
9:00 PM - ES2.6.39
Self-Templating Scheme for the Synthesis of Nanostructured Transition-Metal Chalcogenide Electrodes for Capacitive Energy Storage
Chuan Xia 1 , Husam Alshareef 1
1 , King Abdullah University of Science and Technology (KAUST), Jeddah Saudi Arabia
Show AbstractBecause of their unique structural features including well-defined interior voids, low density, low coefficients of thermal expansion, large surface area and surface permeability, hollow micro-/nanostructured transition-metal sulfides with high conductivity have been investigated as a new class of electrode materials for pseudocapacitor applications. Herein, we report a novel self-templating strategy to fabricate well-defined single- and double-shell NiCo2S4 hollow spheres, as a promising electrode material for pseudocapacitors. The surfaces of the NiCo2S4hollow spheres consist of self-assembled two-dimensional mesoporous nanosheets. This unique morphology results in a high specific capacitance (1263 F g–1 at 2 A g–1), remarkable rate performance (75.3% retention of initial capacitance from 2 to 60 A g–1), and exceptional reversibility with a cycling efficiency of 93.8% and 87% after 10000 and 20000 cycles, respectively, at a high current density of 10 A g–1. The cycling stability of our ternary chalcogenides is comparable to carbonaceous electrode materials, but with much higher specific capacitance (higher than any previously reported ternary chalcogenide), suggesting that these unique chalcogenide structures have potential application in next-generation commercial pseudocapacitors.
9:00 PM - ES2.6.40
Transparent, Flexible and Stretchable Supercapacitors Using Ag-Au-Polypyrrole Core Shell Nanowire Mesh Films
Habeom Lee 1 , Hyunjin Moon 2 , Jinwook Jung 1 , Dongkwan Kim 1 , Jinhyeong Kwon 1 , Jaeho Shin 1 , Sukjoon Hong 3 , Junyeob Yeo 4 , Seung Hwan Ko 1
1 Department of Mechanical Engineering, Seoul National University, Seoul Korea (the Republic of), 2 Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California, United States, 3 Department of Mechanical Engineering, Hanyang University, Ansan Korea (the Republic of), 4 Department of Physics, Kyungbook National University, Daegu Korea (the Republic of)
Show AbstractTransparent, flexible and stretchable energy storage devices have attracted significant interests due to potential to be applied to flexible electronics. Amongst, supercapacitor that uses pseudo mechanism of conducting polymer has advantages in terms of higher specific capacitance compared to EDLC (electrical double layer capacitor) and facile fabrication method through electropolymerization on the current collector. However, no research has been conducted on metal (Silver, Copper) nanowires as current collectors because the conducting polymer’s redox potential for polymerization is higher than that of silver and copper. This problem was solved by coating the surface of silver nanowires with a thin layer of gold since the gold has higher redox potential than the electropolymerizable monomer. In turn, the conducting polymer can be uniformly coated on the surface of gold-coated silver nanowires. The resultant conducting polymer coated Ag@Au NW mesh substrate maintained their electrical property even after 5000 cycle of bending and 100 cycle of stretching up to 50% strain. In addition, supercapacitors made of the conducting polymer coated Ag@Au NW mesh electrodes showed fine transmittance and much increased specific areal capacitance from 100 to 500% compared to Ag@Au core shell NW based supercapacitor. These results substantiate the potential of conducting polymer coated metal nanowire structure as a strong candidate for development of flexible and stretchable electronics.
9:00 PM - ES2.6.41
Electrochemical Properties of Type I Germanium Clathrates Ba8AldGe46–d (0 < d < 16)
Ran Zhao 1 , Hangkun Jing 1 , Svilen Bobev 2 , Candace Chan 1
1 , Arizona State University, Tempe, Arizona, United States, 2 Chemistry, University of Delaware, Newark, Delaware, United States
Show Abstract
Clathrates are materials with cage-like structures known for their unique structures. Their properties are derived from interactions between the cage framework and guest ions inside the cavities. In our group’s prior work, ternary type I clathrates based on M8XdSi46–d (M = Ba; X = Al) were synthesized using thermal annealing or arc-melting and the properties upon electrochemical reaction with Li were investigated. We found that the type I clathrates displayed reversible, solid solution-like insertion of Li with capacities around 40-44 Li per formula unit, which corresponds to about 1 Li/Si.
Here, we extend the studies to type I clathrates based on M8XdGe46–d (M = Ba, K; X = Al, Li) in order to observe the electrochemical properties of Ge-based clathrates for the first time. For the Ba-Al-Ge system, post-cycling characterization with XRD shows amorphization of the material after 50 cycles. The first lithiation and delithiation as high as 1314 mAh/g and 432 mAh/g at a 25 mA/g rate were observed for germanium clathrate with composition Ba8Al0Ge46, corresponding to 207 and 68 Li/Ge. The first cycle capacity decreased as the Al content increased, and after 30 cycles, the reversible number of Li inserted into the electrodes was around 40 – 50 per f.u., with the exception of Ba8Al16Ge30 which was about 20. Comparison of the Ba-Al-Ge system with the analogous Si one suggests that the clathrate cage-volume and presence of framework vacancies may play an important role in the differences between the electrochemically induced phase changes observed.
9:00 PM - ES2.6.42
Solvation Effect on Lithium-Sulfur Electrochemical Reaction in Sub-Nano Confinement
Chengyin Fu 1 , Juchen Guo 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractRechargeable lithium–sulfur (Li–S) batteries continue to be one of the most promising technologies for electrochemical energy storage. However, due to the solubility of lithium polysulfides in the electrolyte, there are many intervened processes involved during charge-discharge leading to low cycle stability, shuttle reaction and redistribution of lithium sulfide at the cathode. Despite the complexity of Li-S electrochemical reactions, most of the challenges are originated from the liquid phase reactions. Therefore, a fundamental question of both scientific and technological importance remains: is it possible to restrict the sulfur-containing electroactive species in the solid state during the Li–S electrochemical reaction? If possible, this hypothesized solid-state Li–S electrochemical reaction would have transformative implications for altering the electrochemical processes and performance of Li–S batteries.
To answer this question, we investigate two factors that play decisive roles in Li–S electrochemical processes: the size of the sulfur confinement (i.e. pore size in the carbon hosts) and the type of electrolyte solvents. To precisely capture the subtle changes in Li–S electrochemical behavior due to the different sulfur confinement size, a series of porous carbon hosts with different pore sizes (1, 2, 2.5, 3 nm) are selected. In addition, two electrolytes, ether-based electrolyte (TEGDME) and carbonate-based electrolyte (EC/DEC) with very different polysulfides solubility are utilized for the study. The results demonstrate a clear correlation between the size of sulfur confinement and the resulting Li–S electrochemical mechanisms. In particular, when sulfur is confined within sub-nano pores, we observe identical lithium–sulfur electrochemical behavior, which is distinctly different from conventional Li–S reactions, in both ether and carbonate electrolytes. We propose that Li ions can only enter the sub-nano pores through desolvation, therefore, the Li-S electrochemical reaction in the sub-nano pores is in solid state. As the results, any Li-ion electrolyte satisfying the electrochemical stability and conductivity requirements should work with the sub-nano confined sulfur cathode, since the solid-state mechanism does not involve or require lithium polysulfide dissolution or polysulfide/electrolyte compatibility.
To further study the effect of Li-ion solvation on the Li-S reaction in the sub-nano confinement, electrolytes based on a series of ethereal solvents (dimethoxyethane, diglyme, triglyme, tetraglyme, and 15-crown-5) are studied. With combination of electrochemical analysis, spectroscopic characterization and DFT-based computation, our results revealed the clear effect of solvation energy of different solvent molecules to Li-ion on the Li-S electrochemical reactions in the sub-nano confinement.
9:00 PM - ES2.6.43
Nanoscale Surface Evolution in Li-Rich Mn-Rich Layered Oxide Cathodes
Chengcheng Fang 1
1 , University of California, San Diego, La Jolla, California, United States
Show AbstractAs the capacity-determining component of lithium ion batteries, cathode materials have been extensively studied to gain higher energy density and longer cycle life. Among all cathodes, lithium-rich layered oxide compounds, xLi2MnO3 (1 − x)LiMO2 (M = Ni, Mn, and Co), have been considered as a promising next-generation cathode candidate, as they can deliver reversible discharge capacity over 280 mAh g-1 with an average voltage of 4 V vs. Li/Li+ when cycled between 2 – 4.8 V. Surface properties influence electrochemical behaviors significantly. In the present work, scanning transmission electron microscopy and electron energy loss spectroscopy (STEM/EELS), X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS) have been utilized to systematically study the detailed surface oxygen and transition metal (TM) ions evolution at different state of charge during the first cycle of the Li-rich Mn-rich layered oxide Li7/6Ni1/6Mn1/2Co1/6O2. XPS analysis reveals surface Ni and Co ions are slightly reduced during plateau region due to oxygen oxidation; low coordinated oxygen is found start from 4.0 V, along with the extraction of Li ions upon charging; in plateau region, both low coordinated oxygen and peroxo-like species (O2n-) present. STEM-EELS results after the first cycle indicate the reduction of Mn ions and oxygen local environment change within 2 nm on the surface.
Symposium Organizers
Yuan Yang, Columbia University
Mauro Pasta, University of Oxford
Kristin Persson, University of California, Berkeley
Jia Zhu, Nanjing University
Symposium Support
BICI Collaborative Innovation
Bio-Logic USA
Gotion Inc.
Jiangsu Qingtao Energy S&
T Co., Ltd.
ES2.7: Group VI Cathodes—Oxygen-Based Redox
Session Chairs
Mauro Pasta
Daniel Steingart
Thursday AM, April 20, 2017
PCC North, 200 Level, Room 224 A
9:15 AM - *ES2.7.01
Oxygen Redox in 3D Transition Metal Oxide Cathodes
Kun Luo 1 , Matthew Roberts 1 , Peter Bruce 1
1 , University of Oxford, Oxford United Kingdom
Show AbstractThe need for better batteries has never been greater. The energy density of lithium batteries is currently restricted by the cathode material, delivering ~ 160-180 mAh g-1.1 New high-energy-density cathode materials are much sought after. The so called lithium-rich layered oxide materials (e.g. Li1-x[Li0.2Mn0.6Ni0.2]O2), exceed the limit of conventional charge storage (defined as charge stored by transition metal redox reactions). The source of this “extra capacity” has been explained previously by a number of models including oxygen loss, electrolyte decomposition and anion redox. Recently, we and others have identified and quantified the charging process in Li[Li0.2Ni0.13Co0.13Mn0.54]O2 and Li1-x[Li0.2Mn0.6Ni0.2]O2, including direct experimental evidence of a dominate O redox process balanced with a minor contribution from oxygen loss when these materials are charged beyond 4.4 V.2-7 The location and nature of the electron-hole states on oxygen have also been probed. The conclusions of this work and that of other researchers working to understand anion redox provide us with guidance on future directions towards higher energy density cathode materials.
References
1. Goodenough, J. B.; Kim, Y. Chem Mater 2010, 22, (3), 587-603.
2. Luo, K.; Roberts, M. R.; Hao, R.; Guerrini, N.; Pickup, D. M.; Liu, Y. S.; Edstrom, K.; Guo, J. H.; Chadwick, A. V.; Duda, L. C.; Bruce, P. G. Nat Chem 2016, 8, (7), 684-691.
3. Luo, K.; Roberts, M. R.; Guerrini, N.; Tapia-Ruiz, N.; Hao, R.; Massel, F.; Pickup, D. M.; Ramos, S.; Liu, Y. S.; Guo, J.; Chadwick, A. V.; Duda, L. C.; Bruce, P. G. J Am Chem Soc 2016, 138, (35), 11211-8.
4. Koga, H.; Croguennec, L.; Menetrier, M.; Mannessiez, P.; Weill, F.; Delmas, C. J Power Sources 2013, 236, 250-258.
5. Koga, H.; Croguennec, L.; Menetrier, M.; Mannessiez, P.; Weill, F.; Delmas, C.; Belin, S. J Phys Chem C 2014, 118, (11), 5700-5709.
6. Sathiya, M.; Rousse, G.; Ramesha, K.; Laisa, C. P.; Vezin, H.; Sougrati, M. T.; Doublet, M. L.; Foix, D.; Gonbeau, D.; Walker, W.; Prakash, A. S.; Ben Hassine, M.; Dupont, L.; Tarascon, J. M. Nat Mater 2013, 12, (9), 827-835.
7. Seo, D. H.; Lee, J.; Urban, A.; Malik, R.; Kang, S.; Ceder, G. Nat Chem 2016, 8, (7), 692-7.
9:45 AM - *ES2.7.02
Anion-Redox Batteries and Lithium Metal Protection
Ju Li 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractLi batteries with anion-redox cathode such as Lithium-Sulfur and Lithium-“solid oxygen” chemistries [Nature Energy 1 (2016) 16111; Nano Letters 15 (2015) 1796] share a lot of common features. In this talk I will discuss the roles of soluble redox mediators in electrolyte, and various strategies to improve the cycle life of Lithium metal anode. I will also address Lithium-matched full-cell performance. Especially, the new “solid oxygen” anion-redox cathode [Nature Energy 1 (2016) 16111], with an amorphous Li2O/Li2O2/LiO2 mixture stabilized by interfacial wetting with porous Co3O4, shows a mass density exceeding 2.2g/cm3 and a discharge capacity of 587 Ah/kg at 2.55 V vs. Li/Li+, with a very stable cycling performance in EC/DEC electrolyte (only 1.8% capacity loss after 130 cycles in lithium-matched full-cell tests against Li4Ti5O12 anode). The cathode shows round-trip overpotential loss of only 0.24 V, a five-fold improvement compared to gas-evolving Li-air battery. Moreover, the cathode is automatically protected from O2 gas release through shuttling of superoxoradical species in carbonate electrolytes, which shunts the voltage to below 2.95 V however overcharged.
10:15 AM - ES2.7.03
High Areal Loading Holey Graphene Air Cathodes for Lithium-Oxygen Batteries
Yi Lin 1 , Jae-Woo Kim 1 , John Connell 2
1 , National Institute of Aerospace, Hampton, Virginia, United States, 2 Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, Virginia, United States
Show AbstractMaterials for air cathodes in lithium-oxygen batteries are of critical importance in hosting the discharge products and, ideally, catalyzing both oxygen reduction and oxygen evolution reactions during discharge and charge. Although there have been reports on air electrode materials of very high capacity per unit weight such as carbon nanotubes and graphene, the areal loading level and thus the areal cell capacity were usually very small, making such cells far from sufficient for practical applications. Increasing areal loading of air electrodes is required, but remains a challenging task in consideration of obstacles such as much longer and more torturous ion transport paths and much increased chance of blocked oxygen diffusion channels when the cathode becomes significantly thicker. In this presentation, air electrodes made from holey graphene, a structural derivative of graphene that exhibits in-plane holes on each sheet, will be discussed. The holey graphene air electrodes with high areal loading were facilely made using a binder-free and solvent-free process due to the unique structural properties of this material. Importantly, these electrodes exhibited high areal capacity for lithium-oxygen batteries with retained capacity per unit weight and cyclability, making them a viable option toward practical applications. Detailed reaction mechanisms, methods for additional catalyst loading, and architectural assembly of these high areal loading air electrodes will be also presented and discussed.
10:30 AM - ES2.7.04
Novel High Power Solid State Sodium-Air Batteries
Ramin Rojaee 1 , Zhennan Huang 1 , Reza Shahbazian-Yassar 1
1 Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois, United States
Show AbstractSince four decades ago, sodium has been introduced to replace lithium-ion batteries due to its cost-effectiveness and abundance of natural sources for sodium, while developing high-performance Na-ion battery is still challenging [1]. Meanwhile, metal–air batteries are known to have a great potential to provide a high energy density which has a theoretical capacity 1605 Wh/kg [2].
To date, the most promising electrolyte for sodium is liquid electrolytes such as NaPf6/NaClO4 in Organic solvent with the ionic conductivity of 10-3 S/cm [3]. It is already known that this type of electrolyte would arises serious safety challenges in terms of flammability and environmental issues. These types of electrolytes, are not stable in O2-rich electrochemical environment and decompose the organic electrolyte [4], also are highly prone to forming dendrite especially against metal anode. Therefore, a novel solid state electrolyte with a high ionic conductivity, sustainable mechanical strength and good cyclability would be a promising candidate for the sodium-air battery. Thus, sodium/sodium peroxide system with efficient solid electrolyte could be a highly-efficient battery design. Herein, we report a novel sodium solid electrolyte in a set of porous carbon material as the air/oxygen cathode vs. pristine sodium metal as the anode with ionic conductivity of 2×10-4 S/cm at room temperature with a wide electrochemical window between 1-3 V vs. Na/Na+.
References
(1) Song, S.; Duong, H. M.; Korsunsky, A. M.; Hu, N.; Lu, L. Sci. Rep. 2016, 6 (August), 32330.
(2) Hartmann, P.; Bender, C. L.; Vračar, M.; Dürr, A. K.; Garsuch, A.; Janek, J.; Adelhelm, P. Nat. Mater. 2013, 12 (3), 228–232.
(3) Ponrouch, A.; Marchante, E.; Courty, M.; Tarascon, J.-M.; Palacín, M. R. Energy Environ. Sci. 2012, 5 (9), 8572.
(4) Zhang, Z.; Lu, J.; Assary, R. S.; Du, P.; Wang, H. H.; Sun, Y. K.; Qin, Y.; Lau, K. C.; Greeley, J.; Redfern, P. C.; Iddir, H.; Curtiss, L. A.; Amine, K. J. Phys. Chem. C 2011, 115 (51), 25535–25542.
ES2.8: Aqueous and Organic Systems
Session Chairs
Mauro Pasta
Daniel Steingart
Thursday PM, April 20, 2017
PCC North, 200 Level, Room 224 A
11:15 AM - *ES2.8.01
Safe Electrolytes for Li-Ion Batteries
Chunsheng Wang 1 , Fudong Han 1 , Chongyin Yang 1 , Fei Wang 1 , Kang Xu 2
1 , University of Maryland, College Park, Maryland, United States, 2 , Army Research Lab, Adelphi, Maryland, United States
Show AbstractThe energy density of liquid electrolyte Li-ion batteries has been significantly increased in recent years due to the advance in both electrode materials and electrolytes. However, further enhancement of the energy density of liquid organic electrolyte Li-ion batteries without scarifying the safety become more difficult due to flammable nature of liquid organic electrolytes and high energy stored in the small cells. Nonflammable aqueous and solid state electrolytes have been attracted more attention for safe Li-ion batteries. The main challenges are the low energy density for aqueous Li-ion batteries and poor cycle life for all-solid state Li-ion batteries. In this talk, we will report the strategies to enhance the energy density of aqueous Li-ion batteries through further extending the electrochemical stability window of water-in-salt electrolytes and using the high capacity electrodes. As for the solid state Li-ion batteries, we systemically investigated the interface impedance and nano-structured cell design that significantly extend the cycle life.
11:45 AM - *ES2.8.02
Exploiting Rough Metallic Growth for Secondary Battery Anodes
Daniel Steingart 1 , Tanya Gupta 1 , Greg Davies 1
1 , Princeton University, Princeton, New Jersey, United States
Show AbstractFor many good reasons, the goal of the secondary metal anode is flat. Flat to start, flat to end. But 50 years of engineering reducing systems has taught us that for many metals, particularly zinc and lithium, the system would rather not be flat.
We looked to see what happens when zinc is formed well beyond the limiting current and found that the zinc takes on a “hyper-dendritic” morphology that is seldom reported in the literature, and never used within a battery. This zinc grows in a manner that is at first glance counterintuitive: a nearly superconformal foam. TEM analysis indicates that true diffusion limited growth is taking place, but at the nanoscale. At the micron scale, what is observed is a collection of anisotropic dendrites growing in a controlled fashion as a “foam front”. Most interesting is that this foam has a different electrochemical potential than “bulk zinc” (50 mV less reducing than bulk zinc), likely because the active surface is edge-dominated as opposed to face-dominated. When we repeatedly charge and discharge this “hyper-dendritic” form of zinc to 50% of its capacity, the foam becomes progressively more compact, growing “inwards”, instead of forming the usual large anisotropic protrusions. This performance compares favorably with zinc foams produced through other methods.
We believe this happens because every growth site is equally favorable (or unfavorable). In other words, when we form the zinc far from equilibrium conditions (high rate, well beyond the limiting current), and cycle the zinc close to equilibrium conditions (low rate, well under the limiting current), the zinc “cycles toward flat.” This is in contrast to the prevailing wisdom that plate metal batteries need to be flat. In further studies that are in progress, we are confirming that the highly-dendritic zinc formed in this manner cycles in a more predictable fashion than “bulk” zinc, and the even reaction rate across the surface of the foam retards ZnO passivation significantly.
In this presentation we will consider the benefits and detriments of this approach, and examine feasiblity beyond zinc.
12:15 PM - ES2.8.03
Hexacyanochromates—Open-Framework Crystal Structure Anode Materials for Sodium-Ion Batteries
Samuel Wheeler 1 , Matteo Salamone , Mauro Pasta 1
1 , University of Oxford, Oxford United Kingdom
Show AbstractNa-ion batteries (NIBs), which replace lithium with abundant and inexpensive sodium, have received a great deal of attention recently[1]. Similarities in the manufacturing process between NIBs and LIBs may significantly accelerate their technological advance[1,2] . Nevertheless, several scientific challenges still need to be resolved before the performance of NIBs becomes competitive with that of LIBs. In particular, the higher negative redox potential of Na compared to that of Li results in lower cell voltages and consequently lower energy densities[1]. Moreover, the larger size of Na+ relative to Li+ (1.02 versus 0.69 Å) causes slower solid-state diffusion in the active materials and leads to lower energy efficiencies when the batteries are rapidly charged or discharged[3].
Prussian Blue analogues (PBAs) have been explored for many different applications because of their ease of synthesis and intriguing electrochemical and magnetic properties. Their general chemical formula is AxP[R(CN)6]1-y x V x nH2O (A: mobile cations; P: nitrogen-coordinated transition metal ion; R: carbon-coordinated transition metal ion; V: [R(CN)6] vacancy). PBAs typically possess the well-known, face-centered cubic crystal structure with the Fm-3m space group, in which transition metal ions are linked together through cyanide (CN) ligands. Each unit cell consists of eight sub-unit cells and therefore contains eight interstitial sites that can host various ions, such as Li+, Na+, K+, NH4+, Rb+, alkaline earth divalent ions, and zeolitic water. The open framework nature of the cubic structure, which contains open <100> channels and interstitial sites, enables rapid solid-state diffusion of a wide variety of ions. Recently, we and others have utilized PBAs as battery electrodes with excellent cycle life and rate performance in both aqueous and organic electrolytes for NIBs[4–6].
Here, we introduce hexacyanochromates as negative electrode materials for NIBs. Chromium hexacyanochromate, in particular, shows the lowest insertion potential of all the PBAs at about 1.5V vs Na+/Na, maintaining the same open framework crystal structure and therefore the same properties in terms of rapid kinetics and low cost.
References
[1] Kim, Adv. Energy Mater. 2012, 2, 710–721.
[2] Yabuuchi, et.al Nat. Mater. 2012, 11, 512–517.
[3] Ong, Energy Environ. Sci. 2011, 4, 3680–3688.
[4] Lee, Nat. Commun. 2014, 5, 5280.
[5] Pasta, Nat. Commun. 2014, 5, 3007.
[6] Pasta, J. Mater. Chem. A 2016, 4, 4211–4223.
12:30 PM - ES2.8.04
Light-Weight and Corrosion-Resistant Current Collector for Aqueous Li-Ion Batteries
Saman Gheytani 1 , Yanliang Liang 1 , Yan Yao 1 2
1 , University of Houston, Houston, Texas, United States, 2 , Texas Center for Superconductivity, Houston, Texas, United States
Show AbstractThe use of low-cost and light-weight aluminium as current collectors in aqueous Li-ion batteries with water-based electrolytes is restricted by corrosion reactions caused by the aggressive ions in the aqueous environments. Here we report for the first time using highly corrosion-resistant Al foil with the chromate conversion coating (CCC Al) as current collector for cathodes in aqueous Li-ion batteries. Coating aluminium with chromium compounds is currently the most effective way to inhibit corrosion of aluminium and its alloys. The protection with the CCC is two-fold: (1) an impervious hydrated chromium(III) oxide serving as a physical barrier on the surface and (2) the chromium(VI) ions stored in the coating provide active corrosion protection.
We have experimentally demonstrated that CCC Al foil is resistant to corrosion when used as the current collector of LiMn2O4 electrodes. The cyclability of these electrodes are on par with or better than those observed for electrodes fabricated on stainless steel and titanium substrates. In contrast, electrodes fabricated on untreated Al foil saw serious corrosion of the substrate within the initial 10 cycles. Interestingly, CCC also effectively suppress oxygen evolution reaction at high potentials, leading to improved Coulombic efficiency of up to 99%. The increased overpotential for oxygen evolution was attributed to the occupation of active chemisorption sites and inhibition of electron transfer on the substrate surface by the chromium compounds. These results may open a new insight into the design of high-performance and high-stability cathode electrodes for aqueous Li- and Na-ion batteries with a higher cell-level energy density.
12:45 PM - ES2.8.05
Voltage and Capacity Control of Polyaniline Based Organic Cathodes—An Ab Initio Study
Yingqian Chen 1 , Sergei Manzhos 1
1 , National University of Singapore, Singapore Singapore
Show AbstractPolyaniline (PANI) is a promising organic cathode material for electrochemical batteries. Its specific capacity is limited by irreversible formation of pernigraniline base, and its energy density is limited by the voltage which could be improved. We present an ab initio study of PANI and PANI functionalized with functional groups which lead to increased voltage and stabilization of the pernigraniline salt. Specifically, the oxidation potential achieved by functionalization with CN on the nitrogen is computed to be 1.3 V higher than that of pristine PANI oligomer, leading to a higher voltage, and the formation of the pernigraniline base is predicted to be simultaneously suppressed, leading to a higher reversible capacity. Therefore, functionalized PANI could be a promising candidate of organic cathode for metal-ion batteries.
ES2.9: 3D Oxide Cathodes
Session Chairs
Matthew McDowell
Chunsheng Wang
Thursday PM, April 20, 2017
PCC North, 200 Level, Room 224 A
2:30 PM - *ES2.9.01
Combining Li-Excess and Reversible Oxygen Charge Transfer to Achieve High Capacity Cathodes
Gerbrand Ceder 1
1 , University of California, Berkeley, Berkeley, California, United States
Show AbstractThe highest energy density cathode materials are currently found among the layered compounds based on Ni,Co and Mn, but achieving much more than 200mAh/g has become difficult. Two new ideas are promising to obtain substantially higher cathode capacity: 1) By using a substantial amount of Li-excess, cathodes can be made tolerant to metal disorder thereby enabling the use of a much larger group of transition metals, while achieving capacities well above 200 mAh/g. 2) Reversible redox process that take place on the oxygen ions rather than on the transition metal ions are now well established and can reduce the transition metal content of cathode compounds. I will explore the physics of both these new directions and demonstrate with several examples how they have enabled novel high-capacity cathodes.
3:00 PM - *ES2.9.02
Considering Factors of Lithium-Rich Oxide Layered Cathodes for Practical Application in Li-Ion Batteries
Jaephil Cho 1
1 , UNIST, Ulsan Korea (the Republic of)
Show AbstractThe lithium- rich oxide layered cathodes (LRC) exhibit one of the highest specific energies (~900 Wh kg-1) among all the cathode materials. However, the practical applications of LRC cathodes are still hindered by several significant challenges, including voltage fade, large initial capacity loss, poor rate capability and limited cycle life. In this talk, I am going to present the recent progress and in depth understandings on the application of LRC cathode materials from a practical point of view. Several key parameters of LRC cathodes that affect the LRC/graphite full-cell operation are systematically analyzed. These factors include the first-cycle capacity loss, voltage fade, powder tap density, and electrode density. Further, voltage loss under storage at 60degree wil be discussed. New approaches to minimize the detrimental effects of these factors will be presented.
3:30 PM - ES2.9.03
Where is the Capacity Limit—A Perspective of Polyhedral Structure
Zhenlian Chen 1 , Jun Li 1
1 Ninbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo China
Show AbstractThe search for new material to improve energy density of Li-ion battery is one of today's challenging issue. The energy density is production of redox potential difference between cathode and anode with capacity. Intensive research efforts have been focused on search or design cathode with high capacity, which is key to make breakthrough for lithium ion battery. Then, where is the theoretical limit of capacity? From the point view of redox mechanism, redox couple determines the thoeretical capacity. However, recent reports pointed out that he redox of aion also contribute to capacity. New materials are reported having higher and higher capacity including Li2Ru3/4Sn1/4O3, Li4Mn2O5, Li3NbO4. In the perspective of polyhedra piling of crystal structure, within the two most popular colse-packed stackng modes of AB and ABC stacking of oxygen ions, there are octahedral intersitial sites layers sandwiched by two times tetrahedral sites layers. If the octahedral sites are occupied by cations, the upper limit compositional ratio of Li respective to oxygen is not beyond one, such as in Li2MnO3 and Li3NbO4; it is not beyond two where the tetrahedral sites are occupied by Li, such as in anti-fluorite Li5FeO4 and Li6CoO4. Unfortunately, the reported high capacity is obtained under very low current condition for the octahedral structured Li-rich cathode materials mentioned above and evenly the reversibility is extremely poor for the tetrahedral structured cathodes. Then, what is the determinal factor of the capacity limit? Oxide cathodes are charge-transfer insulators (LiCoO2 etc.) or mostly Hubbard-type insulators (LiFePO4 etc.). Electron mobility is too low may severelyt hinder the (de)lithiation processes. In this talk, we will discuss the relation of conductivity to polyhedral connections between cation-oxygen polyhedra for diverse cathode materials.
3:45 PM - ES2.9.04
The Effect of Magnetic Interactions on Structural Stability of LiNi1-yCoyO2
Eunseok Lee 1 , Hakim Iddir 3 , Roy Benedek 2
1 Mechanical and Aerospace Engineering, University of Alabama, Huntsville, Huntsville, Alabama, United States, 3 Materials Science Division, Argonne National Laboratory, Argonne, Illinois, United States, 2 Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
Show AbstractDeveloping advanced cathode materials that provide high specific energy and power is essential for the commercialization of Li-ion batteries for electric vehicles. The layered LiNi1-yCoyO2 (NC) received attentions as a promising candidate due to its cheaper material cost and competitive electrochemical performance but suffers from its poor structural stability over electrochemical cycling. Thorough understanding of the origin of poor structural stability will be useful to rectify the structural stability issue as well as increase the capacity of NC.
In this talk, we present our first-principles study on the structural stability of NC. Spin-atom cluster expansion based on the density functional theory (DFT) calculations was performed to find stable states of NC. The cationic mixing was accounted for by assuming that each cationic lattice site can be occupied by any of Li, Co, or Ni. The result predicted four stable states at zero temperature: LiNi0.8Co0.28O2, LiNi0.67Co0.33O2, LiNi0.67Co0.44O2 and LiNi0.5Co0.5O2, as well as many metastable configurations at finite temperature (under 600 K), especially for low y, which agrees with the experimental observations on the range of solid-solution phase NC. Interestingly, many of metastable states contained Ni ions in Li-layer (Ni-antisite ions) but they tended to have less Ni-antisite ions as y increased. It was also observed that the Jahn-Teller distortion was removed with Ni2+ and Co-substitution.
DFT calculations with HSE06 functional were additionally performed to investigate the mechanism of Co substitution in the Ni-antisite suppression. We found that the Ni-antisite ions are usually Ni2+ that would be produced as a result of disproportionation: 2Ni3+ → Ni2+ + Ni4+. Despite the presence of the unfavorable oxidation state Ni4+, increase of energy by the disproportionation is offset by removing the geometric frustration of antiferromagnetic spin ordering between Ni ions. The actual increase of energy was very low, within the range of thermodynamic energy fluctuation at finite temperature. As Co, substituted for Ni, is diamagnetic like Ni4+, it enables the antiferromagnetic spin ordering for all paramagnetic ions without the disproportionation (and production of Ni-antisite ions). In addition to intralayer Co-Co and Co-Ni interactions, the significance of interlayer interactions is also demonstrated quantitatively.
4:30 PM - ES2.9.05
Nanoscale Surface Disorder in Li-Substituted P3/O3 Layered Cathodes for Sodium-Ion Batteries
Qun Huang 1 , Weifeng Wei 1 , Peng Wang 2
1 State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan, China, 2 College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu, China
Show AbstractSodium-ion batteries (SIBs) have been considered as a promising candidate in the next generation energy storage applications owing to the enormous supply of sodium. However, the electrochemical performance and structural stability of Na-ion cathodes upon cycling do not meet the demanding requirements for SIBs. In this study, we propose a novel strategy to introduce small amount of O3 phase in Li-substituted P3-type layered electrode materials to achieve enhanced electrochemical properties. XRD structural refinement, aberration-corrected STEM and XPS depth profiling are employed to understand the structure evolution aroused by Li-substitution. XRD refinement results show that the Li-substitution leads to the formation of a new O3 phase in the P3 layered matrix, and significantly changes the crystallographic information of P3 layered structure. STEM and XPS depth profiling results confirm that alkali metal layer in O3 phase is occupied by lithium ion and the integrowth of P3 and O3 leads to the surface disorder in the layered cathode materials. The biphase surface disorder in this layered P3/O3 composites exert a positive impact on the electrochemical properties of cathode materials.
4:45 PM - *ES2.9.06
A Comparison between Classical Layered Oxides and Lithium-Excess Layered Oxides—Pushing the Limit of Intercalation Compounds
Y. Shirley Meng 1
1 , University of California, San Diego, La Jolla, California, United States
Show AbstractThis work provides novel insight into the oxygen activity and its correlation with the chemical environment of transition metals at the surfaces and sub-surfaces of layered transition metal oxides in lithium batteries: a classical layered and a Li/Mn-rich layered oxide. The surface oxygen activity in battery materials are historically challenging to be analyzed due to the lack of proper techniques that can simultaneously probe the unoccupied oxygen 2p and transition metal 3d orbitals. The energy range of soft X-ray covers both the oxygen K-edge and transition metal L-edges, the combination of which can provide precise information on the local transition metal-oxygen (TM-O) octahedral crystal field. We take advantage of unique features of soft X-ray absorption spectroscopy (s-XAS) and electron energy loss spectroscopy (EELS) to investigate the differences in the oxygen activity between the classical layered oxides and Li rich layered oxides and the impact of such difference on the surrounding TM-O environment, during the first cycle and after a number of high voltage cycles. The experimental data will be carefully interpreted with the help of first principles computation. With a quantitative comparison between the classical layered oxides and lithium rich layered oxides, we hope to provide a strategy to effectively control the oxygen activities in layered oxides, especially when lithium concentrations are low (high voltage range).
This work is funded by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231, under the Advanced Battery Materials Research (BMR) Program (formerly known as BATT)
5:15 PM - ES2.9.07
Morphological and Structural Changes during Electrochemical Cycling in Li-Rich Layered Oxides for Next Generation Li-Ion Batteries
Minghao Zhang 1 , Haodong Liu 1 , Chengcheng Fang 1 , Y. Shirley Meng 1
1 NanoEngineering, University of California, San Diego, La Jolla, California, United States
Show AbstractLi-rich layered oxides, either as a solid solution or as a nano-composite of layered Li2MnO3 and Li(TM)O2 (TM=Ni, Co, Mn), draw significant attention as the next-generation cathode materials for high-energy-density Li-ion batteries in electric vehicles. However, there are many issues still unclear, and numerous scientific challenges of these materials that must be overcome to realize their utilization in commercial Li-ion batteries. The first drawback is the irreversible voltage degradation process that limits cycle life. Modified co-precipitation synthesis is introduced to obtain morphology controlled Li-rich material without ammonia addition. This unique design increases meso-structure morphological stability compared with the sample with large secondary particles as proved by Transmission X-ray Microscope. As a result, the voltage decay and capacity loss during long term cycling have been minimized to a large extent.
On the other hand, lattice oxygen plays an intriguing role in the electrochemical process of Li-rich material through a reversible redox process as well as an irreversible oxidation with O2 gas release. To prevent oxygen gas generation, oxygen vacancies have been proposed to form on the surface of the morphology controlled Li-rich layered oxides through the design of a gas-solid interface reaction (GSIR). Dynamic structural changes during the initial two electrochemical cycles of GSIR Li-rich layered oxides are investigated with In operando synchrotron X-ray diffraction (SXRD). Different electrochemical reaction regions dominated by either cations or anions redox are identified in the shifts of the lattice parameters during the first cycle. Changes in lattice parameters, oxygen positions, and microstrain help to explain the lithium de-intercalation mechanism in this class of materials.
5:30 PM - ES2.9.08
A New Degradation Mechanism in Layered Oxide Cathode Materials
Soroosh Sharifi-Asl 1 , Adam Tornheim 2 , Fernando Soto 3 , Perla Balbuena 3 , Zhengcheng Zhang 2 , Reza Shahbazian-Yassar 1
1 , University of Illinois at Chicago, Chicago, Illinois, United States, 2 Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States, 3 Department of Chemical Engineering, Texas AM University, College Station, Texas, United States
Show AbstractSince the first discovery of Li ion batteries (LIBs), enormous research has been dedicated to understanding of failure mechanisms in Li-ion batteries. However, some aspects of cathode degradation in Li-ion batteries are not addressed yet.
LiNixMnyCo (1-x-y)O2 is one of the most widely used cathode materials in LIBs. High energy density (200 mAhg−1) has made it a good candidate for electric vehicles and grid storage. Attempting to increase the capacity through increasing the cut-off voltage, however, causes unfavorable phase transitions namely spinel and rock salt phase formation. Oxygen desorption phenomena that occurs along with the so-called phase transitions is also of great importance, as released oxygen can react with electrolyte cause battery failure. Nevertheless, these are not the only unwanted processes that cathode materials undergo when cycled to high voltages according to our findings.
In this study we utilized aberration corrected transmission electron microscopy together with analytical spectroscopy to study LiNixMnyCo (1-x-y)O2 that has undergone an extensive high voltage cycle (4.6 V for 120 hours). Atomic resolution imaging confirms the formation of spinel and rock salt phases at the surface of the particle. Interestingly, electron energy loss spectroscopy (EELS) indicates not only the change in the valence of the transition metals, corresponding to oxygen release, but also it points out the extensive dissolution of Co from the cathode structure. Our EELS results also indicates presence of Fe in the sample which might be result of substitution of Fe with dissolved Co originating from casing of the coin cell. Based on our EELS mapping analysis, Co dissolution has happened homogenously in several particles examined to date, which was not reported before to our knowledge. This results may open up new insights into decay mechanism of cathode materials and takes a further step toward achieving high-voltage Li-ion batteries.
ES2.10: Poster Session II
Session Chairs
Kristin Persson
Yuan Yang
Jia Zhu
Friday AM, April 21, 2017
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - ES2.10.01
Electrodeposition of Si and Sn-Based Amorphous Films for High Energy Novel Electrode Materials
Serena Gallanti 1 , Melanie Loveridge 1 , Rohit Bhagat 1
1 , University of Warwick, Coventry United Kingdom
Show AbstractIn order to replace incumbent graphite anodes, this study aims to develop novel, high density, amorphous alloy anodes for versatile applications within Li-ion, Li-S and Na-ion batteries. In particular, we focus on Si- and Sn-based alloy (from binary to quaternary metallic glasses) anodes to demonstrate long cycle life and durability. In this case, electrodeposition has been selected as the main approach due to scalability, cost effectiveness and its potential to fine tune the properties of the resulting films. Moreover, electrodeposited electrodes do not need conductive agents or binders and so are inherently more energy dense.
In the first instance, the galvanostatic electrodeposition of amorphous tin from a sulfate-based acidic bath on copper substrates has been studied. SEM analysis of the deposited films revealed that electrodeposition is suitable to generate films with thickness values in the range 2-40 mm. However, the XRD analysis has highlighted that a large variety of intermetallic Cu-Sn crystalline phases are formed, rather than amorphous tin, due to the high solubility of copper in tin at room temperature. Initial results from the electrochemical characterization of these development films demonstrated a relatively short cycle life – this is not surprising in a non-optimized single element system.
Sn electrodes are susceptible to volume change (≈300 vol. %), but this can be limited by using carbonaceous co-materials to decrease the crystallite sizes. For this reason, graphene has been added to the tin electroplating solution. The comparison of films obtained with/without graphene in the electroplating bath has shown that the morphology and thickness are strongly affected by the presence of this carbon. As yet no significant improvement of cycle life has been observed but further work on the composite formulation can change this, e.g. its influence over impedance changes, microstructure and general mechanical properties.
Secondly, silicon-based materials have been investigated in non-aqueous plating baths due to their high moisture-sensitivity. Si has been electrodeposited galvanostatically or potentiostically from propylene carbonate baths. Part of the Si investigation focuses on the electrodeposition of Si-Sn binary alloys; the aim is to decrease the deposition times (1h ≈ 1 mm) and generate amorphous / nano-crystalline films that are capable of reversible cycling without pulverization.
Finally, solid electrolyte materials such as ionomeric and/or ionically conducting ceramic films can be applied as artificial SEI-type films to suppress electrolyte decomposition at low voltage. Future experiments will focus on the integration of ionomeric thin-film/alloy combinations. To our knowledge, no literature exists on amorphous alloys with integrated surface protection and we present herein our preliminary findings in this innovative research domain.
9:00 PM - ES2.10.02
Silicon Electrode Degradation Analysis Using Laboratory Based X-Ray Tomography
Romeo Malik 1 , Donald Finegan 2 , Qianye Huang 1 , Serena Gallanti 1 , Francesco Iacoviello 2 , Geoff West 3 , Paul Shearing 2 , Rohit Bhagat 1 , Melanie Loveridge 1
1 Electrochemical Engineering Group, Warwick Manufacturing Group, University of Warwick, Coventry United Kingdom, 2 Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London United Kingdom, 3 Steels Processing Group, Warwick Manufacturing Group, University of Warwick, Coventry United Kingdom
Show AbstractLi-ion batteries are the energy storage technology of choice for next generation automotive and grid storage applications. In recent years considerable studies have shown that crystalline silicon is a promising negative electrode candidate. However, silicon still has major performance issues associated with the volume expansion which can result in cracking and pulverisation of active particles. Subsequent charge-discharge cycling causes repeated disruption of the solid-electrolyte interphase (SEI, a major source of continued irreversible Li loss) layer where it continues to form and grow. These phenomena culminate in conductivity loss and capacity fade. This poor electrochemical stability of silicon anode is preventing it from commercialization. Despite the numerous studies and evolution of sophisticated in-situ characterisation techniques, relatively little is understood still about the microstructural evolution and its impact and relation to the cell performance during operation and failure.
X-ray computed tomography (CT) has been proven to be an effective tool to explore the hierarchical structure of battery electrodes and for diagnosing battery failure mechanisms at multiple- length scales. X-ray CT, in conjunction with impedance spectroscopy and associated physical characterization, will be employed to capture and quantify key aspects of the evolution of internal morphology and resistance build up. This includes characterisation of SEI growth, porosity changes and conductive network breakdown during charge-discharge operation. This approach will enable us to observe and quantify failures in Li-ion batteries at the electrode level, and thus facilitate construction of better electrode architectures.
This study aims to investigate modes of degradation in composite silicon anodes for Li-ion battery operating under different aging time i.e. number of cycles of charge and discharge and comparing microstructural architecture with performance. This will enable better design and formulation of longer-lasting batteries.
9:00 PM - ES2.10.03
Rational Doping Design of Ni-Rich Layered Oxide Cathode Materials for Li-Ion Battery
Fantai Kong 1 , Roberto Longo 1 , Chaoping Liang 1 , Yongping Zheng 1 , Kyeongjae Cho 1
1 , University of Texas at Dallas, Richardson, Texas, United States
Show AbstractNi-rich layered oxides LiNi1-xMxO2 (x = 0.1-0.2, M = Ni, Co, Mn, Al, etc.) have been widely viewed as the next generation cathode materials for Li ion battery, due to their high capacities (>200 Ah/kg), high energy densities (>800 Wh/kg), high ionic diffusivity (10-8 cm2/s) and high electronic conductivity (10-1 S/cm). However, due to dopant cluster formation, these oxides faced many challenges towards ultimate commercialization such as easy incorporation of anti-site defects during synthesis, safety problem at increased temperature and poor cycling retention.[1,2] To suppress these problems, a variety of doping strategies by substituting Ni ion with cation elements or O ion with anion elements have been widely applied. However, due to insufficient theoretical understanding of doping effects on different properties, the rationalized doping design was hard to be realized.[3-6] In the present work, we have applied density functional theory to study in atomic scale the underlying mechanisms of current issues faced by Ni-rich oxides.[3-6] Based on these understandings, we have examined how common dopants (Mg, Al, Ti, V, Mn, Fe, Co, F, S, Cl, etc.) would tune different issues. The obtained results provided significant insights into the nature of Ni-rich oxides as cathode materials, and revealed conflicting effects of certain dopants on battery performances. From these findings, the rationalized realistic doping strategies have been proposed. We expect that this work could also inspire further doping studies and promote related research and materials doping design for other relevant cathode materials.
[1] W. Liu, et al., Angew. Chem. Int. Ed., 2015, 54, 4440-4457.
[2] F. Schipper, et al., J. Electrochem. Soc, 2017, 164, A6220-A6228.
[3] C. Liang, et al., J. Phys. Chem. C, 2016, 120, 6383-6393.
[4] C. Liang, et al., J. Power Sources, 2017, 340, 217-228.
[5] F. Kong, et al., Chem. Mater., 2016, 28, 6942-6952.
[6] R.C. Longo, et al., J. Phys. Chem. C, 2016, 120, 8540–8549
This work was supported by Samsung Advanced Institute of Technology (SAIT). Theoretical calculations were done in the Texas Advanced Computing Center (TACC).
9:00 PM - ES2.10.04
Unravelling the Origin of Irreversible Capacity Loss in NaNiO2 for High Voltage Sodium Ion Batteries
Liguang Wang 1 2 , Jiajun Wang 2 , Xiaoyi Zhang 3 , Yang Ren 3 , Geping Yin 1 , Pengjian Zuo 1 , Jun Wang 2
1 , Harbin Institute of Technology, Harbin China, 2 , Brookhaven National Laboratory, Upton, New York, United States, 3 , Argonne National Laboratory, Lemont, Illinois, United States
Show AbstractDriven by the successful application of their analogies LiMO2 (M = transition metal) in lithium-ion systems, layered transition metal compounds, NaMO2, have attracted widely attention due to their simple structure and relatively high capacity among the various cathode materials. Among these transition-metal NaMO2 cathodes, owing to its relatively higher operating voltage and theoretical capacity, Ni based O3-type NaNiO2 has been studied extensively. However, the low reversible capacity and poor cycle stability of NaNiO2 barre their practical application in sodium ion batteries. Overcoming these challenges requires comprehensive understanding of the underlying structural change mechanism in NaNiO2.
It was found that the multiple phase transformation (O′3-P′3-P′′3-O′′3) occurs at voltage range of 1.8-3.4 V, corresponding to only 0.2 Na ions extracted from the pristine material during the first charge. A significant increased capacity was reported recently that 0.85 Na+ per formula unit could be extracted and 0.62 Na+ ions can be intercalated back into the structure during the first charge and discharge with the voltage range of 2.0-4.5 V. By the comparison of the XRD patterns of NaNiO2 electrodes charging to 3.75 and 4.5 V, an unidentified new phase was observed at the highly charged sample (4.5 V), which may contribute to the improved capacity. More recently, the phase changes of NaNiO2 cathode during the first charge/discharge process at the voltage range of 1.5-4.0 V were reinvestigated by in situ lab XRD, and two new phases (O′′′′3 phase at the end of discharge and P′′′3 structure at 3.38 V) were identified. Despite that these previous work pointed out a basic understanding of the phase evolution process during reversible Na ions intercalation/de-intercalation process, the origin of the initial irreversible capacity loss has not been investigated yet.
In this work, we combined synchrotron based in operando transmission X-ray microscopy, high-energy X-ray diffraction, high-resolution X-ray diffraction, and electrochemically measurements to visualize the phase transformation during the first two cycles. The structure of pristine NaNiO2 material was investigated by the refined HR-XRD. Phase mappings at various states of charge were directly obtained by TXM-XANES technique, and a correlation between the phase transformation process and electrochemical performance is presented. It is suggested that the irreversible structure evolution primarily occurs at low voltage (below 3.0 V) and high voltage (above 4.0 V), tracking by in situ HE-XRD during the first cycle. Galvanostatic intermittent titration technique measurement also indicated that this irreversibility is related to Na+ diffusion and reaction kinetics behaviors at low voltage (3.0 V) and high voltage (over 4.0 V).
9:00 PM - ES2.10.05
Nickel–Cobalt Layered Double Hydroxide Based Nanoflakes Electrode Materials for High-Performance Electrochemical Energy Storage Devices
Imran Shakir 1
1 SET, King Saud University, Riyad Saudi Arabia
Show AbstractAs we are facing increasing challenges of diminishing fossil fuel and global warming, there is increasing interest in developing advanced and cost effective electrochemical energy storage devices for diverse applications including mobile power supply to portable electronics, electric vehicles (EVs) or hybrid EVs (HEVs). To this end, layered double hydroxides (LDHs) have gained considerable attention in the past decade as a unique class of electrode materials due to their multiple cations, flexible ion exchangeability and tunable compositions. With abundant slabs and electrochemically active sites, the LDHs can be used to produce energy storage devices with both the double-layer capacitance and Faradaic pseudocapacitance. In the current report we have synthesized hierarchical porous nanoflakes of Nickel–Cobalt Layered Double Hydroxide through cost-effective and scalable chemical precipitation method exhibited high specific capacitance (850 Fg-1), excellent rate capability (81% capacity retention at 10 A g-1) and cycling stability (only 4.8% loss after 5000 cycles).
9:00 PM - ES2.10.06
Room-Temperature Synthesized Amorphous Nano-Aggregates of Antimony Sulfide and Their Na-Ion Storage Performance for Seawater Flow Batteries
Soo Min Hwang 1 , Junsoo Kim 1 , Youngsik Kim 1 2
1 , Ulsan National Institute of Science and Technology, Ulsan Korea (the Republic of), 2 Energy Materials and Devices Lab, 4TOONE Corporation, Ulsan Korea (the Republic of)
Show AbstractRechargeable batteries have been recognized as the central to effective ways for sustainable development of our societies. As one of electrical energy storage (EES) systems, rechargeable batteries allow us to efficiently utilize the intermittent energy generated from renewable resources by integration into the electrical grid. Seawater flow batteries have recently been developed by our group for large-scale EES systems, featuring an eco-friendly, hybrid-type Na-air battery utilizing naturally abundant seawater as the catholyte in a flow-type, open-structure. This battery employs multiple electrolytes, which comprise two liquid electrolytes of non-aq. electrolyte and seawater (catholyte) separated by a Na-ion-selective ceramic electrolyte of Na3Zr2Si2PO12. During the charge and discharge processes, the evolution/reduction reactions of gaseous O2 and/or Cl2 phases occur at the cathode side, while the redox reactions of Na ions occur at the anode side. By applying an appropriate Na-ion-storing electrode as the anode, this battery indeed exploits natural seawater to store electrical energy without the use of Na metal.
In this study, we synthesized amorphous (a-) antimony sulfide (SbSx) nanoparticle aggregates using a facile polyol-mediated process at room temperature and examined the Na-ion storage capability as an anode for seawater flow batteries. The a-SbSx nano-aggregates electrode displayed good cycling stability and rate property for Na-ion storage, compared to the commercial, crystalline Sb2S3 electrode. This result was mostly likely due to the spherical-shaped nanoparticles and their amorphous structure, which bestow isotropic natures in the structural and morphological aspects, enabling to tolerate the large volume changes throughout the multiple charge-discharge cycling. The Na-metal-free seawater battery full-cell (a-Sb2S3|seawater) displayed a relatively low discharge capacity in the initial cycles, but showed an increased capacity of 470−485 mAh/g with an average discharge voltage of ~1.9 V and Coulombic efficiencies of 83−88% during the 50th to 70th cycles.
Acknowledgements
This work was supported by the 2017 Research Fund (1.170012.01) of UNIST (Ulsan National Institute of Science and Technology).
9:00 PM - ES2.10.07
Electrochemical Characterization of Silicon-Coated Vertically Aligned Carbon Nanofibers Anode in Gel Polymer Electrolyte for All-Solid-State Lithium-Ion Batteries
Gaind Pandey 1 , Jun Li 2
1 , Xavier University of Louisiana, New Orleans, Louisiana, United States, 2 , Kansas State University, Manhattan, Kansas, United States
Show AbstractLithium-ion batteries (LIBs) have become essential energy storage devices for today’s portable electronics and the development is underway for supporting future hybrid electric vehicles due to their high energy densities. Silicon-lithium alloys are one of the most attractive anode materials for next-generation LIBs because of their high theoretical capacity, low electrode potential etc. Improving the safety of the LIBs for high energy density applications is another important aspect of current research focuses. This paper reveals that nanostructured Si-coated VACNF anodes in a solid-like, flexible gel polymer electrolyte (PVdF-HFP/EC-DMC-LiTFSI), exhibit excellent performance toward a highly stable LIB. The 3D nanostructured provides a high capacity of 3450 mAh g-1 at C/10.5 (or 0.36 A g-1) rate in gel polymer electrolyte which is comparable to the liquid electrolyte. The flexible gel polymer electrolyte fully infiltrates into the spaces between VACNFs and helps to accommodate the stress/strain induced by the volume expansion of Silicon during charge-discharge. The development of compatible gel polymer electrolyte with Si-based anodes may suggest an important step for the development of Si-anode based solid-state LIBs.
9:00 PM - ES2.10.08
Vertically Oriented MoS2-3D Carbon Nanotubes Hybrid Composite as an Anode Material for Next Generation Li-Ion Batteries
Mumukshu Patel 1 , Eunho Cha 1 , Nitin Choudhary 2 , Chiwon Kang 1 , Wonki Lee 3 , Jun Yeon Hwang 3 , Wonbong Choi 1
1 , University of North Texas, Denton, Texas, United States, 2 NanoScience Technology Center, Materials Science & Engineering, University of Central Florida, Orlando, Florida, United States, 3 Institute of Advanced Composites Materials, Korean Institute of Science and Technology, Jeonbuk Korea (the Democratic People's Republic of)
Show AbstractThe advent of advanced electrode materials has led to performance enhancement of traditional lithium ion batteries (LIBs). However, the fulfillment of LIBs are still limited by the specific capacity of graphitic anode material (~372mAh/g) and there is continuous quest to develop high capacity novel material without compromising electrochemical performance. MoS2 has been emerging candidate for anode material possessing theoretical specific capacity of ~670 (mAh/g), but there is volumetric variation due to lithiation/delithiation. In this approach, a unique binder-free electrode of 3-dimensional carbon nanotubes (CNTs) coated by MoS2 has been fabricated by a chemical vapor deposition (CVD) and direct magnetron sputtering method. Vertically oriented nanoflakes of MoS2 are strongly bonded on 3D CNTs with diameter of 50-100nm. The 3D geometry for the accommodation of active material (MoS2) provides high surface area with active electrochemical sites, enhance ion diffusivity, and compensates volumetric expansion of MoS2. The electrochemical performance of the binder-free 3D CNTs-MoS2 electrode shows very high areal capacity of ~1.65mAh/cm2 with an areal density (of MoS2) of ~0.35mg/cm2 at 0.5C rate; it also shows capacity retention of ~82% after 50 cycles. The unique architecture of 3D CNTs-MoS2 is suggestive to be a promising anode for next generation Li-ion batteries with high capacity and long cycle life.
9:00 PM - ES2.10.09
Semiconductor Based Supercapacitor with High Capacitance and Intrinsic Smart Functions
Minshen Zhu 1 , Chunyi Zhi 1
1 , City University of Hong Kong, Hong Kong Hong Kong
Show AbstractSupercapacitors are regarded as promising energy storage technologies due to their characteristic advantages of high power density and stable cycling performance. Much progress has been made to overcome the major disadvantage to demanded high-energy-density supercapacitors by using pseudocapacitive materials such as metal oxides or conductive polymers. Meanwhile, integrated smart functions for supercapacitors have attracted considerable attention. With regard to the multifunction of materials, metal oxides, especially semiconductors, have great advantages. In this talk, we present a typical semiconductive metal oxide, WO3 as the electrode material for supercapacitors, which shows high capacitance, as well as the intrinsic smart functions. First, we successfully fabricate the hexagonal phase WO3 (h-WO3) by adapting a capping agent (NaCl). The prepared h-WO3 show very high capacitance: almost highest among WO3 based supercapacitors. After thorough investigation of the mechanism behind the high capacitance, we reveal that large hexagonal tunnels in h-WO3 efficiently facilitate the insertion of protons, which greatly enhance the energy storage ability. Furthermore, the capacitance of h-WO3 shows apparent response to the solar light. This is because the h-WO3, due to its semiconductive nature, will generate excited electrons under bias potential and illumination of the solar light. Subsequently, the excited electrons effectively facilitate the insertion of protons into large hexagonal tunnels so that the capacitance is enhanced. In turn, this light dependent capacitance served as the solar light indicator that is intrinsically integrated to the WO3 based supercapacitors. In addition to the function of the light indicator, the WO3 self can effectively indicate its energy storage status as it is a well-known electrochromic material. One step further to the qualitatively indication from the color change of WO3 during the charging/discharging process, we successfully quantify the relationship between the energy storage status and the color change of WO3 by relating it with the characteristic optical transmission of WO3. WO3 is further incorporated into supercapacitors based on other high-performance materials to indicate the energy storage status, which shows the immense potential in application of all kinds of supercapacitors.
9:00 PM - ES2.10.10
Study of Initial Cell Conditioning Effects on Lithium-Sulfur Cells Undergoing Simulated EV Driving
Jeffrey Bell 1 , Rachel Ye 1 , Selcuk Temiz 1 , Kazi Ahmed 1 , Zafer Mutlu 1 , Leon Peng 1 , Andrew Scott 1 , Daisy Patino 1 , Mihri Ozkan 1 , Cengiz Ozkan 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractWith an increase in demand for longer lasting batteries, researchers have turned towards sulfur based batteries owing to its high energy density, low cost, and abundance of material. In this study, we investigate the effects of initial cell conditioning on lithium sulfur cells by means of electrochemical impedance spectroscopy (EIS), Gravimetric Intermittent Titration Technique (GITT), Cyclic Voltammetry (CV), and Galvanostatic Cycling (GCPL). Cells were tested under simulated driving conditions (city & highway, 36.5 miles) while measurements were taken at the end of each simulated day and each simulated week. The cells were analyzed for one month of simulated driving and for up to 40 cycles. EIS shows capacity fading corresponding to a decrease in charge transfer resistance. GITT shows increased diffusion rates corresponding to changes in the cathode related to shuttling and the formation of the solid electrolyte interface (SEI). CV shows consistent electrochemical peaks in good agreement with literature while also observing a potential shift related to higher ionic conductivity. GCPL shows severe capacity degradation as a result of rapid current changes on the cell. Here we present the effects of three different initial cell conditioning procedures on the health and stability of lithium sulfur cells.
9:00 PM - ES2.10.11
Protecting Silicon-Film Anodes in Lithium-Ion Batteries Using an Atomically-Thin Graphene Drape
Shravan Suresh 1 , Ziping Wu 2 , Stephen Bartolucci 4 , Rahul Mukherjee 3 , Nikhil Koratkar 1
1 , Rensselaer Polytechnic Institute, Troy, New York, United States, 2 Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou China, 4 , U.S. Army Armaments Research Development and Engineering Center, Benet Laboratories, Watervliet, New York, United States, 3 , Enermat Technologies, LLC, Clifton Park, New York, United States
Show AbstractSilicon (Si) shows enormous potential to replace traditional graphitic anodes in Lithium (Li)-ion batteries due to its exceptionally high theoretical specific capacity of ~4200 mAh g-1. After over a decade of intense activity in this field, the community has moved away from bulk Si films to nanoparticles of Si. There are some very good reasons for this for instance, lithiation of Si films leads to large volume expansion and stress-induced pulverization. The solid electrolyte interface (SEI) for Si films is also notoriously unstable leading to continual capacity fade with charge/discharge cycling. By contrast, nanostructures of Si such as nanowires and nanoparticles are far less prone to fracture compared to bulk Si films and their SEI can be stabilized by carbon based coatings. However this increases manufacturing complexity and can result in reduced volumetric energy density due to the porosity of Si nanoparticle based electrodes. Here we show that contrary to conventional wisdom, Si films can be stabilized by simply ‘draping’ the film with a graphene monolayer. Not only does the graphene drape form a very stable SEI, it exhibits a remarkable toughening effect on the underlying Si film. After electrochemical cycling, the graphene-coated Si films resembled a tough mud-cracked surface in which the graphene capping layer prevented delamination and pulverization. By contrast, Si films without graphene were completely eviscerated within few tens of charge/discharge cycles. Such graphene-draped Si films exhibited long cycle life (> 1000 charge/discharge steps) with an average specific capacity of up to ~1090 mAh g-1. The volumetric capacity averaged over 1000 cycles of charge/discharge is ~3820 mAh cm-3 which is 3-to-7 times higher than the literature for Si nanoparticle based electrodes.
9:00 PM - ES2.10.12
3 in 1—Multifunctional 3D Graphene for Integrated Graphene-Sulfur Cathode, Separator and Current Collector of Li-S Battery
Yu-Yun Hsieh 1 , Lu Zhang 1 , Noe Alvarez 2 , Vesselin Shanov 1
1 Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio, United States, 2 Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio, United States
Show AbstractRecently, lithium-sulfur battery has been extensively studied due to its high theoretical energy density (~2500 Wh/kg), which is 10 times larger than the current state-of-art lithium-ion batteries. Beside the development of carbon materials as cathode materials for Li-S battery, a rational design of the overall Li-S battery is necessary to achieve the optimal performance. In this work, a novel mesoporous three-dimensional (3D) graphene structure is reported for multifunctional applications: current collector, cathode materials and a part of Janus separator for Li-S battery. The mesoporous 3D graphene exhibited a bulk electrical conductivity of ~100 S/cm with a good mechanical integrity that make it promising to be used as flexible current collector as well as scaffold for sulfur particles. The unique surface morphology of 3D graphene contributed a strong Van der Waals force that enables 3D graphene to be intimately attached to polypropylene (PP) separator for a Janus separator structure. Without using any binder materials, conductive additives or metal current collector, the 3-in-1 3D graphene/sulfur/PP (3DSP) multifunctional structure showed a capacity of ~1000 mAh/g at 0.1 C with a sulfur loading of more than 70 wt%. By mitigating the shuttle of polysulfide, the Janus separator structure based on 3DSP also improved the cyclic performance of the Li-S battery, and this improvement was further enhanced by oxygen plasma functionalization as oxygen functional groups have a strong binding energy to polysulfide.
9:00 PM - ES2.10.13
Carbon Coated Wrinkled Silicon Nanoparticles as a High-Rate Anode for Li-Ion Batteries
Bokyung Kim 1 , Jihoon Ahn 1 , Jeiwan Tan 1 , Daehee Lee 1 , Jin-Kyu Lee 2 , Jooho Moon 1
1 1Department of Materials Science and Engineering, Yonsei University, Seoul, Seoul, Korea (the Republic of), 2 , Seoul National University, Seoul Korea (the Republic of)
Show AbstractSeeking for anode materials with high specific capacity, rate capability, and long-term stability is crucial for the commercial applications of lithium-ion batteries (LIBs) including electric vehicles and portable devices. Among possible candidates, silicon (Si) is mostly promising owing to high theoretical capacity, but the use of Si is hindered by the expensive synthetic process to the nanostructured Si as well as intrinsic problems of Si such as large volume change during lithiation/delithiation process, low electrical conductivity, and slow internal diffusion of Li-ion. In this work, we synthesized wrinkled silicon nanoparticles with carbon coating (wSi@C) through magnesiothermic reduction of wrinkled silica nanoparticle (WSN) and subsequent pyrolytic deposition of carbon. Due to an unique valley-like wrinkled structure pseudomorphically transformed from WSN, our wSi@C has enough free volume space within a particle that can accommodate the volume expansion of Si during cycling. Also, this free space on the particle provides a highway of Li-ion which facilitates the Li-ion diffusion to the deep core center. Furthermore, the wall of wrinkle structure enhances the active surface area that enlarges the contact area between Li-ion and Si surface. Finally, the conformal carbon coating allow wSi@C to retain both structural stability and enhanced electrical conductivity. Compared with spherical silicon nanoparticle coated by carbon (sSi@C), wSi@C exhibited higher electrochemical performance as a LIBs anode owing to the unique wrinkled structure. The wSi@C achieved a high specific capacity of 900 mAh/g after 100 cycles at the current density of 500 mA/g, which was 80 % to the initial reversible capacity. Also, even at a high density of 10 A/g, wSi@C presented a reversible capacity of 300 mAh/g. Our wSi@C is effectively fabricated from WSN by inexpensive and scale up synthetic process, therefore successfully demonstrated the potential of Si based anode with enhanced performance for LIBs.
9:00 PM - ES2.10.14
Trash to Treasure—Bio-Inspired Synthesis of Nanostructured Materials via Controllable Diffusion System for Energy Storage
Xinghua Meng 1
1 Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan, United States
Show AbstractNature is the greatest creator, building massive sophisticated materials. The amazing structures in nature consist of nanostructures, which can be built in mild conditions without special devices. For human beings, we are capable of developing nanomaterials now. However, most strategies are still based on complex procedures or under harsh conditions such as high pressure and high temperature. Here, an idea was generated from trash – eggshell, which inspired us to build all kinds of unique nanomaterials on substrates. Based on controllable diffusion of ions, nanostructured Co(OH)2 and Ni(OH)2 can be easily built in simple salt solutions. The deposited nanomaterials were evaluated as free-standing electrodes for supercapacitors with satisfactory performance. After simple treatment, they were transformed into sophisticated composite materials for lithium-ion batteries. Moreover, this bio-inspired strategy can be employed to build nanomaterials in artificial devices based on ion-exchange membrane for scale-up fabrication in future. After mastering the mechanism of this controllable diffusion strategy, we could build various nanomaterials for energy storage conveniently.
9:00 PM - ES2.10.15
Boron-Modified Silicon Oxycarbide/Graphene Composite Paper Electrode for Electrochemical Energy Storage
Monsuru Abass 1 , Muhamed Kolathodi 1 , Lamuel David 1 , Gurpreet Singh 1
1 Mechanical and Nuclear Engineering, Kansas State University, Manhattan, Kansas, United States
Show AbstractBoron modification of silicon oxycarbides ceramics is one of the sustainable means of improving electrochemical energy storage properties of electrode materials. In this study, thin film composites comprising of boron nitride nanotube-modified silicon oxycarbides (SiOC-BNNT) ceramic supported on reduced graphene (rGO) sheets were synthesized via vacuum filtration followed by pyrolysis in a flowing argon gas. This configuration ensures a uniform dispersion of the ceramic on rGO sheets and stabilization against aggregation due to BNNTs that form a continuous network connecting the ceramic particles. In electrochemical energy storage application, boron is believed to improve the electronic conductivity and chemical stability of SiOC by modifying its nanodomain structure. Thin films of graphene-supported SiOC modified with different percentages of BNNTs (SiOC-BNNT/rGO) were synthesized, characterized and tested as a lithium-ion battery (LIB) and supercapacitor electrode. Among the synthesized thin film composite papers, SiOC containing 0.25 wt.% and 0.5 wt.% BNNT supported on rGO displayed the optimum electrochemical properties as a LIB anode and supercapacitor electrode, respectively. As observed in this study, the capacity of SiOC-BNNT/rGO as an electrode material for electrochemical energy storage indicates the existence of an optimum wt.% BNNT required to enhance the desirable properties of SiOC composites.
9:00 PM - ES2.10.16
Fabrication of Aligned Carbon Nanotubes and Magnetic Nanowires Using Porous Polymer Template
Dmitri Zagorskiy 1 3 , Ilya Doludenko 7 , Sergey Bedin 1 2 , Balram Tripathi 4 5 , Kirill Frolov 1
1 , Center for Crystallography and Photonics of RAS, Moscow Russian Federation, 3 , Institute for Problems in Mechanics RAS, Moscow Russian Federation, 7 , National Research University Higher School of Economics, Moskva Russian Federation, 2 , Moscow State Pedagogical University, Moscow Russian Federation, 4 Department of Physics, University of Puerto Rico, San Juan, Puerto Rico, United States, 5 Department of Physics, S S Jain Subodh P College, Jaipur India
Show AbstractTwo types nanomaterials were obtained in this work using Matrix Synthesis technique. The first were nanowires (NWs) of iron group metals (Fe, Co or Ni and alloys - Fe-Ni, Fe-Co) The second were Multiwall Carbon Nanotubes (MWCNTs). In both cases polymer track matrixes (TMs) have been used as templates.
The ensembles of magnetic NWs: The galvanic process was investigated for these materials. and it was found that the main stage-deposition of metal inside the pores - has non-linear character due to diffusion limitation. The specific features of the final stage (formation of the “caps”) were also studied.
SEM: demonstrated that the diameter of NWs is higher than the diameter of the pores of host matrix-possibly due to polymer compression. It was also demonstrated that the diameter is altered over a length of NW The composition of two-component NWs differs from the composition of grooving electrolyte and this composition changes along the NW.
X-rays analysis demonstrated that the grain size of NWs depends on deposition speed.. Mössbauer spectroscopy gave possibility to estimate hyperfine parameters for Fe-Co NWs. For Fe-Ni NWs it was supposed that the spectra could be presented as superposition of at least three magnetic sextets with hyperfine parameters Bhf 27-33 T. It was shown (vibration magnetometer) that Fe-Co samples have “hard magnetic” properties (c. f. 1000-1200 Oe), while Fe-Ni samples were “soft magnetic” (c. f. 70-100 Oe),. The dependence of these parameters on the synthesis conditions was demonstrated: the increase of voltage leads to decrease of the grain size.
MWCNTs are perspective for using in charge-storage units –as supercapacitor . The alignment of groups of these MWCNTs inside the parallel pores of dielectric polymer track matrix should improve their electrical and storage properties. In our work deposition of CNTs in the TMs was performed by using electrochemical system :two electrodes with DC current. The process of deposition demonstrates that the length of the CNT channels in the pores of TMs depends on the deposition time and current. The length of the CNTs channels inside the pores of track membranes have been controlled by deposition time and their alignment have been performed by magnetic field (5 KOe). Charging and discharging study of these aligned CNTs track membrane composites have been performed by using Solatron system. The applied maximum and minimum potential range was 4.8 V and 3.03 volts respectively and the obtained current value was approx 1.9 micro amp.The SEM images of aligned CNTs in TMs shows uniformly distributed channels of equal size for charge transport and storage.
The charge storage capacity and energy density has been found to be enhanced due to aligned MWCNT channels in TMs which will be used as flexible and free standing charge storage system .
Acknowledgments. Russian Grant RFBR 15-08-04949.
Authors thank Dr.V.Artemov (IC RAS) for SEM and Prof. M.Chuev (Ph. Tech Inst RAS) for magnetic measurements.
9:00 PM - ES2.10.17
Activated Edge Oriented Graphene on Carbon Nanofibers for Kilo-Hertz Ultrafast Electric Double Layer Supercapacitors
Nazifah Islam 1 , Guofeng Ren 1 , Zhaoyang Fan 1
1 Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas, United States
Show AbstractUltrafast electric double layer capacitors (EDLCs) with large capacitance density could find many applications by replacing the bulky and low-density electrolyte capacitors. This requires EDLC work at hundreds to kilo-hertz frequencies, while conventional EDLC only can be charged/discharged far below 1 Hz. Here activated edge oriented graphene or thin-graphite (EOG) on carbon nanofibers (CF) (EOG/CF) is reported to fabricate highly dense and ultrafast EDLCs. EOG was grown around carbon fibers in a plasma chemical vapor deposition process. The as-grown EOG/CF was subsequently oxidized and then reduced by H2 plasma to make activated EOG/CF structure with large surface area, easily accessible pores, and high conductivity. The activated EOG/CF was filtered onto separator to make an integral electrode/separator structure for cell assembly. The cells exhibit kilohertz ultrafast charging-discharging rate and a large volumetric capacitance. Promising results were obtained indicating EDLC based on this structure is promising for working at frequencies above hundreds Hz. The detail fabrication process, material properties and microstructures, particularly the ultrafast EDLC performances will be reported.
9:00 PM - ES2.10.18
Nano-Confined Metal Oxide in Carbon Nanotube Composite Electrodes for Lithium Ion Batteries
Chunlei Wang 1 , Alexandra Henriques 1 , Richa Agrawal 1
1 , Florida International University, Miami, Florida, United States
Show AbstractThe development of high capacity rechargeable lithium-ion batteries (LIBs) is vital given the increasing energy demands that come with the rapidly developing technological landscape in modern day society. From portable technologies and medical equipment to alternative energy sources, the continual improvement of batteries and fuel cells has been rendered invaluable for society to continue improving. One main focus of research toward this objective is the development of advanced electrochemical materials. Metal oxides (MxOy) are materials of particular interest for study given their high theoretical capacities. However, metal oxides often experience substantial volumetric expansion during battery cycling due to their lithium storage mechanisms. Additionally, poor electrical conductivities limit their potential utility. One of the methods proposed to overcome these problems is the confinement of metal oxide particles in the interest of improving their charge storage capability, rate capability, and the longevity of their performance with cycling. Confinement of metal oxide nanoparticles (e.g. SnO2) within carbon nanotubes has been shown to improve the performance of these materials as LIB anodes versus unconfined metal oxides. The increased surface area, enhanced interfacial charge storage, mitigation of volumetric expansion, buffering of internal stresses, and improved electrical conductivity result in better performance. A thin film of the active anode material is deposited onto a current collector via electrostatic spray deposition (ESD) for use in cells to test electrochemical performance. The details of these experimental methodology and the results of characterization of the active materials will be presented.
9:00 PM - ES2.10.19
Study on Chemical Vapor-Deposited Carbon Nanotubes as Electrode Material for Supercapacitor Applications
Ganesh Sainadh Gudavalli 1 , Tara Dhakal 1 , Jim Turner 1
1 , Binghamton University, Binghamton, New York, United States
Show AbstractSupercapacitors, also known as electrochemical capacitors or ultracapacitors are electrochemical energy storage devices that combine the high-energy density of conventional batteries and the high-power density of conventional capacitors. Carbon nanotubes (CNT) and carbon nanofibers (CNF) have been utilized in supercapacitor applications due to their excellent electrical conductivity, large specific surface area, and chemical inertness. We report the capacitance of the entangled carbon nanotubes synthesized on flexible carbon fabric via water-assisted chemical vapor deposition. The CNTs were grown at atmospheric pressure with iron (Fe) as catalyst, ethylene (C2H4) and 5%/95% H2/Ar as precursor gases and aluminum oxide as buffer/barrier layer. The effect of the catalyst thickness (5 and 10nm) and alumina buffer layer (25 and 50nm) on the specific capacitance were studied. The capacitance behavior of CNT's was evaluated by cyclic voltammetry measurements via a three-electrode system. The highest specific capacitance, approximately 56 F/g was obtained in the electrode grown with 5nm Fe thickness, however the specific capacitance varied between 4 F/g – 56 F/g for different sets of CVD runs. The capacitance effect of the CNTs in the form of a nearly rectangular shaped cyclic voltammogram was exhibited along with galvanic charge-discharge curves and electrochemical impedance spectroscopy (EIS). The specific power density of 0.012 KW/Kg and specific energy density 0.15 Wh/Kg were calculated from CD curves.
9:00 PM - ES2.10.20
Hierarchical Carbon Nanotube Microstructures for Ultra-Flexible Li-Ion Batteries
Shahab Ahmad 1 , Davor Copic 1 , Simon Engelke 1 , Chandramohan George 1 , Michael Volder 1
1 , University of Cambridge, Cambridge United Kingdom
Show AbstractWhile considerable progress has been made in the fabrication of flexible and stretchable circuits and displays, flexible batteries needed to power these devices remain challenging and underpowered. Recent, progress in this field includes the use of polymer substrates, composite membranes, paper and yarn based electrodes. However, many of these designs suffer from fast capacity decay, limited flexibility, poor thermal management, and high weight.
To address these problems, we have designed new electrodes which alleviate stress from the electrochemical active material during bending. To achieve this, we populate a flexible current collector with 3D CNT microstructures on which we decorate the electrochemical active material. The base of these CNT structures is anchored in a conductive polymer collector electrode and is as small as possible to avoid stress transfer from this substrate to the active material. The CNT structures then widen into a cone shape to have a large surface area to coat the active material. The unpatterned CNT forests readily crack when they are bent, while our new patterned design does not. Even when folding our electrodes to radii as small as 300 μm no cracks were observed. This radius was limited by our ability to handle the thin films rather the electrode material itself. These electrodes were tested for both half coin cell type as well as full flexible cells. We found that this battery architecture not only imparts excellent flexibility, but also high rate (20A/g), cycling stability (over 500 cycles at 1C with capacity retention over 70%). The electrode fabrication process, which starts by lithographically patterning catalyst particles into rings from which CNTs are grown by thermal chemical vapour deposition (CVD). The CVD process results in the formation of microcylinders that each consists of thousands of vertically aligned CNTs. These cylinders are transformed into cones using elastocapillary aggregation. Next, the cones are transferred by contact printing to a flexible conductive film, with a yield close to 100%.
References:
[1].T. Someya, Nat. Mater. 2010, 9, 879.
[2].R. C. Webb, A. P. Bonifas, A. Behnaz, Y. Zhang, K. J. Yu, H. Cheng, M. Shi, Z. Bian, Z. Liu, Y.S. Kim, W.H. Yeo, J. S. Park, J. Song, Y. Li, Y. Huang, A. M. Gorbach, J. A. Rogers, Nat. Mater. 2013, 12, 938.
[3].J. Ren, Y. Zhang, W. Bai, X. Chen, Z. Zhang, X. Fang, W. Weng, Y. Wang, H. Peng, Angew. Chemie Int. Ed. 2014, 53, 7864.
[4].L. Hu, H. Wu, F. La Mantia, Y. Yang, Y. Cui, ACS Nano 2010, 4, 5843.
[5].M. De Volder, S. H. Tawfick, R. H. Baughman, A. J. Hart, Science 2013, 339, 535.
[6].M. De Volder, S. H. Tawfick, S. J. Park, D. Copic, Z. Zhao, W. Lu, A. J. Hart, Adv. Mater. 2010, 22, 4384.
[7].Shahab Ahmad, D. Copic, C. George and Michael D. Volder, Adv. Mater. 2016, 28, 6705.
[8].Z. Rong, Y. Zhou, B. Chen, J. Robertson, W. Federle, S. Hofmann, U. Steiner, P. GoldbergOppenheimer, Adv. Mater. 2014, 26, 1456.
9:00 PM - ES2.10.21
Influence of Lithiation on Metal Ion Doped (C, Cu, In) Sb2S3 for Energy Storage Application
Sharvanti Pinglay 1
1 , Anna University, Chennai India
Show Abstract
Pure Sb2S3 nanostructures and transition metal doped (Cu, G, and In) Sb2S3 nanostructures were prepared by simple hydrothermal precipitation method. The formation and the material properties were studied by various characterization techniques such as XRD, TGA, SEM and optical absorption studies and demonstrated their significance in energy storage application. The phase analysis by XRD revealed that the synthesized materials were highly crystalline in nature and small fractions of secondary impurities due to the incorporation of dopant were also provoked. The SEM observations confirm the formation of 1D rods of length in micron scale and width in nano scale. The stability of the synthesized samples was estimated from the TGA and the optical adsorption study showed a red shift phenomenon with reduced bandgap supporting the increase in conductivity. The role of metal dopant and the influence of post treatment process lithiation on the energy storage were elucidated by cyclic voltammetry measurements. The measurement showed that the combination of lithiation process and incorporation of metal dopant have increased the specific charge capacitance C p values from 166 Fg -1 to 471 Fg -1 . The increase in capacitance was attributed to the high conducting nature of metal ion which promoted the facile charge transfer between the electrodes. Thus, the present work was highly supported for the energy storage device applications.
9:00 PM - ES2.10.22
Nanostructured Cathode Materials of Lithium-Sulfur Batteries—Progress, Challenges and Perspectives
Kishwar Khan 1 , Sarish Rehman 2 , Zhengtang Luo 1
1 , Hong Kong University, Kowloon Hong Kong, 2 , Peking University, Beijing China
Show AbstractLithium–sulfur batteries (LSBs) possess numerous fold higher energy densities than those of conventional batteries, however their establishment as a dominant niche in modern electronics and grid level storage energy techniques are critically impeded by short cycling life, limited sulfur loading and sever polysulfide shuttling effect. Outrageous achievement has been achieved since last decade in stacking off the aforementioned obstacles by employing various strategies to enhance their performance and making them as promising alternative candidates for the present energy storage technology that shows great potential for the next-generation high-energy system. To promote the breakthroughs in this exciting field, here we will highlight the recent progress on the innovation of the sulfur cathodes with an emphasis on the design of new class materials, engineering of advanced nanostructures and novel cell configuration to enhance the electrochemical stability of LSBs. We will also discuss the future research directions and the remaining challenging issues in the concluding remarks that pave the ways for further significant progress in this field.
References
J. Mater. Chem. A, 2017, Accepted Manuscript DOI: 10.1039/C6TA10111A.
Rehman, S.; Gu, X.; Khan, K.; Mahmood, N.; Yang, W.; Huang, X.; Guo, S.; Hou, Y., 3D Vertically Aligned and Interconnected Porous Carbon Nanosheets as Sulfur Immobilizers for High Performance Lithium-Sulfur Batteries: Adv. Energy Mater. 2016, DOI:10.1002/aenm.201502518.
9:00 PM - ES2.10.23
Quantifying Electrochemical Reactions and Properties of Amorphous Silicon in a Realistic Lithium-Ion Battery Configuration
Hanqing Jiang 1 , Xu Wang 1 , Nik Chawla 1
1 , Arizona State University, Tempe, Arizona, United States
Show AbstractThe development of high-energy storage devices is one of top most important research areas in recent years and rechargeable batteries are anticipated to be the primary sources of power for modern-day requirements. Lithium (Li) ion battery is one such rechargeable batteries that has been investigated because of their high energy density, no memory effect, reasonable life cycle, and one of the best energy-to-weight ratios and has applications in portable electronic devices, satellites, and potentially electric vehicles. Silicon is an attractive anode material being closely scrutinized for use in Li-ion batteries because of its highest-known theoretical charge capacity of 4,200 mAh/g. However, the development of Si-anode Li-ion batteries has lagged behind because of their large mechanical deformation, i.e., up to 400% volumetric change, during electrochemical reactions, which results in fracture, pulverization and early capacity fading. In other words, this coupled mechanics (e.g., volumetric change) and electrochemistry problem is the bottleneck on the development of Si anode Li-ion batteries. Therefore, a fundamental understanding of this coupled behavior of mechanics and electrochemistry will not only advance our knowledge on the failure of Si under lithiation, but also provide a basis to resolve this bottleneck in the development of the promising Si-anode Li-ion batteries.
In this presentation, we will report a systematic study by direct measurement of Li-Si composition using Auger Electron Spectroscopy (AES), micro-nano scale observation of Si expansion using Focus Ion Beam (FIB), and ex-situ measurement of young’s modulus and hardness by nanoindentation during a-Si film lithiation.
9:00 PM - ES2.10.25
Layered MoS2/RuO2 Electrode Material for Enhanced Performance Supercapacitors
Wang Wei 1
1 , University of Electronic Science and Technology of China, Chengdu China
Show AbstractRuO2, because of the high specific capacitance, has been widely recogniced as the promising electrode material for supercapacitors. However, due to high cost, the application of RuO2 was limited. Another problem is that the cycling stability of RuO2 is lower than that of activated carbon electrodes.MoS2 with two-dimensional layer structure and larger specific surface area exhibits excellent capacitance properties and cyclic stability. In this paper, MoS2/RuO2 composites were synthesized by hydrothermal method. The morphology and crystalline type of the synthesized material were examined by XPS, TEM and XRD. The experiment results show the composites have a loose and disordered structure, which can facilitates fast electron transfer rate between the active materials and the charge collector. Cyclic voltammetry, electrochemical impedance spetrometry, and galvanostatic charge-discharge tests indicated that when the loading level of MoS2 reaches 25%, the maximum specific capacitance of MoS2/RuO2 composites reach up to 552F/g, and there is only 6.4% decrease in specific capacitance after 1000 cycles. Compared with the bare RuO2, the MoS2/RuO2 nanocomposites display better supercapacitor characteristics.
9:00 PM - ES2.10.26
High Performance All Solid-State Paper Supercapacitor Based on Nanofibrillar Cellulose (NFC) Composites
Fei Jiao 1 , Xavier Crispin 1
1 , Linköping University, Norrköping Sweden
Show AbstractNanofibrillated cellulose as a remarkable building block for nanocomposites has received great attention in recent years due to its extraordinary mechanical properties, high transparency, lightweight character, large specific surface area, renewability, availability, and potential biocompatibility. In this work we demonstrate the fabrication of paper supercapacitor based on nanofibrillar cellulose (NFC) composites, in which NFC-PEDOT film is used as electrode and NFC-PSSH film is used as electrolyte. Both composite films are prepared by a simple, scalable and cost-effective method. The as-obtained paper supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.
9:00 PM - ES2.10.27
A Cost Effect Route to Synthesis LiFePO4 in a Limited O2 Environment
Fei Gu 1 2 3 , Rany Tith 3 , Alfredo Martinez-Morales 1 2 3
1 Materials Science and Engineering Program, University of California, Riverside, Riverside, California, United States, 2 , Winston Chung Global Energy Center, University of California, Riverside, Riverside, California, United States, 3 College of Engineering Center for Environmental Research and Technology, University of California, Riverside, Riverside, California, United States
Show AbstractFurther reducing the cost of lithium-ion batteries (LIBs) is a major effort by the LIBs industry. In previous work we have shown that LiFePO4 can be synthesized in an open air environment. However, oxidized LiFePO4 is an issue that negetitively impacts the quality of the product. This work proposes a new synthesis method to decrease the production cost for LiFePO4, by synthesizing the material through a solid state reaction in a closed crucible designed to limit the amount of oxygen participating in the reaction. In our approach, iron phosphate (FePO4) powder is preheated to eliminate moisture. Once dried, the FePO4 is mixed with lithium acetate (CH3COOLi), and the mixture is placed in a sealed crucible and heated in a tube furnace. In order to minimize the oxidation of the formed LiFePO4, experimental parameters are optimized along with crucible. X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) are used to characterize the crystal structure and chemical composition of the synthesized material. Furthermore, scanning electron microscopy (SEM) is applied to measure the grain size of synthesized material, study physical properties and characterize topography. The synthesized LiFePO4 is assembled into a half coin cell for electrochemical characterization. The cycleability and performance under different C-rates are tested using an Arbin tester
9:00 PM - ES2.10.28
Novel Tire-Derived Carbon Electrodes for Lithium and Sodium Ion Batteries
Mariappan Paranthaman 1 , Yunchao Li 1 , Kokouvi Akato 1 , Amit Naskar 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractThe main objective of this research is to develop a method to recover carbon from recycled, low-cost, and abundant tires and demonstrate its feasibility as electrodes in energy storage applications. Almost 1 billion scrap tires are generated globally every year. Proper disposal and recycling of waste tires prevent the threats large piles of them pose to the environment and to public health and safety. Hence, recycling hazardous tires to produce value-added products is essential for the sustainability of our society. We have developed recently a method to recover carbon through sulfonation followed by pyrolysis of tires and demonstrated its use as anodes in both lithium- and sodium-ion batteries. To reduce the first cycle loss, we have developed a method through a pre-lithiation process. We will also report the current status of the tire-derived carbon composite powder scale up efforts and its use in energy storage applications.
9:00 PM - ES2.10.29
Development of Chemically Immobilized Sulfur Cathodes for Next-Generation Lithium Sulfur Batteries
Lu Li 1 , Jian Gao 1 , Feng Li 2 , Wencai Ren 2 , Chandra Singh 3 , Hui-Ming Cheng 2 , Nikhil Koratkar 1
1 , Rensselaer Polytechnic Institute, Troy, New York, United States, 2 , Institute of Metal Research, CAS, Shenyang China, 3 Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
Show AbstractLithium sulfur (Li-S) batteries, with specific energy several times that of state of the art Li-ion batteries, have generated great interest and excitement as next generation energy storage systems for portable electronics as well as automotive applications. However, the insulating nature of sulfur/Li2S and the dissolution of lithium polysulphides (LiPSs) in the electrolyte with subsequent parasitic reactions leads to low sulfur utilization and poor cycle life. The integration of nanostructured carbon materials with sulfur is one of the primary strategies for improving the electrical conductivity of the composites and suppression of LiPSs shuttling through physical confinement. However the weak interaction between non-polar carbon-based materials and polar LiPSs/Li2S species leads to weak confinement and easy detachment of LiPSs from the carbon surface. The resulting diffusion of LiPSs into the electrolyte is responsible for rapid capacity decay and poor rate performance.
In this presentation, we present the rational design and development of chemical immobilizers as sulfur hosts towards advanced Li-S batteries by: (1) introducing nitrogen-doped hetero-atoms into graphene for the generation of polar functional groups to enhance the interaction and immobilization of LiPSs species in the electrode;(2) growing ReS2 nanosheets perpendicular to the carbon substrate drastically increases the exposed surface area and sharp edges, which shows strong binding effect with LiPSs based on their similar polar interaction; and (3) depositing few-layer phosphorene nanosheets on a conductive carbon scaffold as polysulfide immobilizer and catalyst to significantly lower the polarization, accelerate the redox reaction and improve the cycle life of Li-S battery. After 500 continuous cycles of charge-discharge, the specific capacity of the Li-S battery with phosphorene is retained above 660 mA h g−1 with only ~0.053% capacity decay per cycle, much better than the baseline battery (without phosphorene) which shows ~0.25% capacity fade per cycle in only 200 cycles under the same test condition. First-principles density functional theory calculations indicate that this improvement is related to phosphorene’s ability to immobilize lithium polysulfides. The binding energy of various LiPSs to phosphorene ranges from 1-3.1 eV, which is significantly greater than a carbon hexatom network (~0.5 eV).
Based on these results, an outlook will be given on how chemical immobilizers could be effectively used to alleviate the dissolution of LiPSs, accelerate the redox reaction and improve sulfur utilization in the Li-S batteries.
9:00 PM - ES2.10.30
Universally Applicable Antimony-Doped Tin Oxide Decoration on Electrodes for High-Energy Density Energy Storage
Gyujin Song 1
1 , Ulsan National Institute of Science and Technology, Ulsan Korea (the Republic of)
Show AbstractGyujin Song1, Jung-In Lee and Soojin Park*1
1School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
As the most widely used energy storage device, lithium-ion batteries (LIBs) have attracted a great attention over the past decades due to their high energy and power density. To extend a range of application, it is inevitable to develop high capacity and highly durable electrodes. Along with structural control, active materials can be improved simply by surface coating method including various metal oxides. We employed a simple but straightforward decoration strategy using antimony-doped tin oxide (ATO) which can be universally applicable to diverse active materials, including lithium cobalt oxide cathode (LCO), silicon (Si) and natural graphite (NG) anode. As well as each half cells result, well-configured full cell composed of ATO coated LCO cathode and ATO coated Si displayed exceptionally high energy density and outstanding electrochemical performance, which outperforms conventional LCO/NG and LCO/Si in terms of cycling stability and rate capability by providing efficient electronic conduction and preventing undesirable interfacial reaction between electrodes and liquid electrolyte.
9:00 PM - ES2.10.31
Freestanding Solid-State Micro-Supercapacitor Based on Laser-Patterned Nanofibers
Yu Song 1 , Xuexian Chen 1 , Haotian Chen 1 , Haixia Zhang 1
1 , Institute of Microelectronics, Peking University, Beijing China
Show AbstractWith the development of portable electronics, the energy storage devices are in great demands. Compared with the conventional supercapacitors with sandwiched structure, the planar micro-supercapacitor (MSC) which can greatly decrease the thickness and maintain excellent electrochemical performance has emerged as an important flexible energy storage device with the elimination of the separator. However, most of the MSCs are employed with complex lithography and substrate transferring process, which are costly and possibly damage the electrodes. Therefore, we fabricate the interdigital MSC through the electrolyte transferring and laser patterning process, which could increase the flexibility without further substrate and simplify the scalable and integrated fabrication without the shadow mask.
Schematic diagram of the MSC includes the nanofibers, electrode, current collector and electrolyte. Each device weighs only 20 mg, which performs good flexibility and portability. Fabrication process begins by electrospinning PVDF nanofibers with large surface area. Then CNT ink is drop-dried until it is saturated as the active materials. Next, gel electrolyte consisting of PVA and H3PO4 is spray coated on the CNT-nanofiber electrodes. After being completely dried by vaporizing excess water, the electrodes are easily transferred to electrolyte film without further substrate. To efficiently promote the charge flow, Au is sputtered beyond the electrodes as current collector. Finally, such freestanding MSC is laser patterned to form the interdigital electrodes.
Using the proposed process, the freestanding MSC with patterned electrodes has been fabricated. The optical microscopic image shows the electrodes have a well-defined shape and sharp boundaries. SEM images could clearly demonstrate the morphology of every process and the cross-section SEM image of the device shows the electrolyte is penetrated into the bottom electrode to enhance the ion exchange. Furthermore, MSCs with 200, 400, 800 μm line-width of finger are designed to investigate the variation of the electrochemical performance. CV curves of these devices are recorded and areal capacitance is calculated at different scan rates. MSC 200 owns higher capacitance (15.6 mF/cm2), which proves that shorten line-width reduces the ions transport path and improves rate capability. Then CV and GCD tests of the MSC 200 are analyzed in detail. As for the cycling stability, it maintains more than 83% capacitance after 2,000 cycles. To further integrate flexible MSCs, the serial connection circuit of MSC 400 is proposed. From the CV curves, an enhanced potential range by the serial units could be provided, and such device performs stably even in the bent conditions. When fully charged, these lightweight and highly flexible devices could be powerful enough to drive a calculator or a wearable LED continuously.
Symposium Organizers
Yuan Yang, Columbia University
Mauro Pasta, University of Oxford
Kristin Persson, University of California, Berkeley
Jia Zhu, Nanjing University
Symposium Support
BICI Collaborative Innovation
Bio-Logic USA
Gotion Inc.
Jiangsu Qingtao Energy S&
T Co., Ltd.
ES2.11: Characterizations
Session Chairs
Matthew McDowell
Mauro Pasta
Friday AM, April 21, 2017
PCC North, 200 Level, Room 224 A
9:15 AM - *ES2.11.01
Five-Dimensional Visualization of Phase Dynamics in Battery Electrodes with Synchrotron Hard X-Ray Nanotomography
Jiajun Wang 1 , Jun Wang 1
1 , Brookhaven National Laboratory, Upton, New York, United States
Show AbstractAnisotropy of ionic and electronic transport extensively exists in a number of solid state materials, determining the functions of many electronic and energy systems, with performance depending on the three dimensional (3D) transport features. Advancing our understanding of the mechanism necessitates the development of advanced tools with in situ capability to track the dynamic phase and structural changes of battery materials at 2D and 3D. The synchrotron hard X-ray imaging technique is particularly interesting for applications in battery studies because of its natural characteristics: it is non-destructive, chemically and elementally sensitive, environmentally friendly, and highly penetrative to enable in situ study of a real battery.
Considerable progress in this field has been reported recently from our group at Brookhaven National Laboratory (BNL), where a new hard X-ray imaging technique, transmission X-ray microscopy (TXM), has been developed and applied to multi-dimensional operando imaging study in energy materials field.[1-7] A unique capability of this technique is that it can provide chemical information at nano-scale spatial resolution, combining with X-ray absorption near edge structure (XANES) spectroscopy.
In this talk, we will present a five-dimensional imaging method (X, Y, Z, energy, and time) based on X-ray absorption near edge spectroscopy nanotomography under in situ electrochemistry in a working battery. We track the 3D chemical phase evolution as a function of charging time for lithium iron phosphate, a representative example involving a first-order phase transformation between a lithium-poor and lithium-rich olivine phases in electrochemical energy storage, and elucidates a strong anisotropy of 3D phase transformation with a preferential phase boundary migration in this olivine material. 5D visualization of the correlation between the electrochemical kinetics and the anisotropic phase propagation provide invaluable information for designing materials with unique functions. We expect this five-dimensional imaging method open new opportunities for energy, materials, environment and life sciences. Challenges and opportunities of TXM technology for energy materials research will be also discussed.
Reference
[1] Wang, J., Chen-Wiegart, Y. K., Eng, C., Shen, Q., Wang, Nat. Commun. 7, 12372 (2016).
[2] Wang, J., Eng, C., Chen-Wiegart, Y. K., Wang, J. Nat. Commun. 6, 7496 (2015).
[3] Wang, J., Chen-Wiegart, Y. K., Wang, J. Nat. Commun. 5, 4570 (2014).
[4] Wang, J., Chen-Wiegart, Y. K., Wang, J. Angew. Chem. Int. Ed. 126, 4549-4553 (2014).
[5] Wang, J. et al. Nat. Commun. 5, 3145 (2014).
[6] Wang, J., Chen-Wiegart, Y. K., Wang, J Chem. Commun. 49, 6480-6482 (2013).
[7] Wang, J. et al. Appl. Phys. Lett. 100, 143107 (2012).
9:45 AM - ES2.11.02
In Situ Tracking of the Structural Chemistry during Synthesis of Ni-Rich Layered Oxides as High-Energy Cathodes for Li-Ion Batteries
Jianming Bai 1 , Feng Wang 1
1 , Brookhaven National Laboratory, Upton, New York, United States
Show AbstractLayered Lithium transition metal oxides LiMO2 (M=Co, Ni, Mn) have been the dominant cathode materials for Li-ion batteries (LIBs) over the decades, and among them, Ni-rich ones, LiNi1-xMxO2 (x<0.5) are of particular interest for large-scale applications of LIBs such as electric vehicles due to their high capacity and low cost. However, synthesis of stoichiometric Ni-rich layered oxides with high structural ordering has been a great challenge, hindering their practical application. A better understanding of the reaction mechanism in the synthesis of LiMO2 helps in overcoming the obstacles. Herein, we report a comparative study using time-resolved in situ X- ray diffraction on the synthesis of LiCoO2, LiNioO2 and LiNi0.8Co0.2O2. The results indicated similar reaction pathways in the production of LiNiO2 and LiNi0.8Co0.2O2, with subtle differences caused by the minor component Co in the latter. In both reactions, the layered oxide phases were generated via direct lithiation of NiO (or solid solution of NiO and CoO); the addition of Co lowered the onset temperature of the target product phase with Co settled first in the Li-M segregation. In contrast to the direct lithiation reactions in producing the Ni-rich oxides, the lithiation process occurred at lower temperature in the formation of Li2Co2O4, a metastable intermediate that bridged the precursors Co3O4, Li2Co2O4 to the target product, the stoichiometric LiCoO2. Taken together, the results suggest that the nature of the cation (i.e., ionic radius, size, valence state) plays a significant role in determining cationic ordering and phase transformation during synthesis of layered oxides.
10:00 AM - ES2.11.03
Elucidating the Mechanism of High-Rate and High-Capacity Lithium-Ion Intercalation in Bulk Complex Oxides
Kent Griffith 1 , Alexander Forse 1 2 , John Griffin 1 3 , Clare Grey 1
1 , University of Cambridge, Cambridge United Kingdom, 2 , University of California, Berkeley, Berkeley, California, United States, 3 Chemistry, Lancaster University, Lancaster United Kingdom
Show AbstractEnergy storage materials with both high capacity and high charge/discharge rate enable applications that require long life, high power, and rapid recharge. Electric double-layer capacitors offer high power and battery electrodes offer relatively high capacity but the combined properties require advanced materials. While nanostructures have dominated this emerging field, there are well-known issues regarding cost, stability, scalability, and safety of nanoparticles for battery applications. Recently, we have demonstrated and characterised complex oxide structures from facile solid-state synthetic methods with promising rate, capacity, and stability for reversible lithium intercalation.1 Dense particles with high packing density of non-nanostructured T-Nb2O5 were shown to intercalate lithium at high rates with capacity performance and retention similar to the best nanostructured analogues; a mechanistic investigation was undertaken to explain this novel behavior.
T-Nb2O5 bronze type and other emerging complex structures with advanced energy storage properties feature low symmetry, large unit cells, site disorder, superstructure, order–disorder transitions, local second–order Jahn–Teller distortions, and mobile lithium atoms, which create severe challenges and interesting opportunities for experimental and computational investigations. Herein, we discuss the structure and properties of i.) crystallographic shear compounds (e.g. TiNb2O7)2 and ii.) tungsten bronze-type phases (e.g. T-Nb2O5)1. Electrochemical results are interpreted with insights from 6/7Li, 93Nb, and 17O solid state nuclear magnetic resonance spectroscopy, in situ x-ray absorption spectroscopy, in situ x-ray diffraction, bond valence sum mapping, and density functional theory. There is a focus on understanding these important structure families and the applicability of advanced characterization techniques to these complex functional oxides.
References
1. Griffith, Kent J.; Forse, Alexander C.; Griffin, John M.; Grey, Clare P. High-Rate Intercalation without Nanostructuring in Metastable Nb2O5 Bronze Phases. J. Am. Chem. Soc. 2016, 138, 8888–8899.
2. Guo, B. et al. A Long-Life Lithium-Ion Battery with a Highly Porous TiNb2O7 Anode for Large-Scale Electrical Energy Storage. Energy Environ. Sci., 2014,7, 2220-2226
10:15 AM - ES2.11.04
In Situ Investigation of Distinct Nanoscale Reaction Pathways in a Sulfide Material for Sodium and Lithium Batteries
Matthew McDowell 1 , Matthew Boebinger 1 , Michael Xu 1 , Xuetian Ma 1 , Hailong Chen 1 , Raymond Unocic 2
1 , Georgia Institute of Technology, Atlanta, Georgia, United States, 2 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractMany alloying and conversion materials show diminished cycle life in sodium cells compared to lithium cells, and this is often attributed to the more significant volume changes that occur because of the larger ionic radius of sodium. However, volume change is not the whole story: the cycling behavior of a material is largely determined by the nanoscale reaction pathways and morphological transformations that occur during insertion/removal of alkali ions. For the development of improved Na-ion batteries, it is therefore critical to understand and control reaction processes within promising materials. Here, nanoscale-to-macroscale transformation pathways are investigated in Cu2S (a sulfide conversion material) during electrochemical reaction with Na and Li. In situ x-ray diffraction reveals that the overall phase transformations in Cu2S electrodes are similar within both Na and Li cells. However, in situ TEM shows that the nanoscale reaction pathways and resulting morphologies differ significantly. During sodiation of Cu2S, an amorphous Na2S film forms on the surface of the Cu2S particles, followed by the destruction of the Cu2S lattice and the formation of large Cu domains. During the lithiation of Cu2S, the sulfur sublattice is nearly preserved during the replacement of the Cu+ ions with Li+. Despite these differences, Na/Cu2S half cells are shown to exhibit excellent cycle life (negligible capacity decay over 400 cycles) for the first time. Thus, although the more substantial volume changes during reaction with Na induce a new reaction pathway compared to the Li case, they do not cause accelerated capacity decay. These findings emphasize the importance of linking detailed reaction mechanisms to electrochemical behavior, and they suggest that other alloying and conversion materials may also be engineered for improved cycle life in Na-ion batteries.
10:30 AM - ES2.11.05
Investigating the Mechanism and Extent of Surface Degradation in Ni-Based Cathode Materials Induced by Electrochemical Cycling
Sooyeon Hwang 1 2 , Se Young Kim 1 , Kyung Yoon Chung 1 , Eric Stach 2 , Seung Min Kim 3 , Wonyoung Chang 1
1 Center for Energy Convergence, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 2 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, United States, 3 Carbon Composite Materials Research Centre, Korea Institute of Science and Technology, Wanju Korea (the Republic of)
Show AbstractNi-rich lithium transition metal oxides have been considered as one of the most promising cathode materials for next generation batteries due to their higher energy density, less toxicity, and lower cost compared with those of LiCoO2. In spite of advantages, structural instability and safety issues of Ni-rich materials during operating are huge drawbacks which should be overcome for wide spread applications. Incorporating other elements into the Ni-rich cathode materials can be an effective method to optimize the figures-of-merits of cathode materials.
In this study, we exploited (scanning) transmission electron microscopy [(S)TEM] and electron energy loss spectroscopy (EELS) to examine the local changes of electronic structures as well as to determine the depth of surface degradation in Ni-based cathode materials (LiNi0.4Mn0.3Co0.3O2, LiNi0.8Mn0.1Co0.1O2, and LiNi0.8Co0.15Al0.05O2) after electrochemical cycles. Even though extensive work has been done to elucidate the degradation mechanism of cathode materials with a number of analytical tools, identifying the degree of structural evolution has not been considered much. STEM-EELS line profiles enable us not only to probe the mechanism of surface degradation but also to quantitatively determine the depth at which metal reduction happens. Both qualitative and quantitative information about material degradation induced by electrochemical cycles offers critical understanding and insight into the rational design of new cathode materials with high capacity and long-term stability. All the details will be available at the meeting.
10:45 AM - ES2.11.06
Non-Invasive in Operando Imaging of Lithium-Sulfur Battery Using Light Microscopy
Nian Liu 1 , Yi Cui 2 , Steven Chu 2
1 , Georgia Institute of Technology, Atlanta, Georgia, United States, 2 , Stanford University, Stanford, California, United States
Show AbstractLithium-sulfur battery could increase the energy density of current Li-ion batteries by 300-500%, but their overall performance (cycle life, Coulombic efficiency, areal capacity, reproducibility) is still not ready for large-scale application. Mechanistic understanding of Li-S battery could provide guidance to overcome the intrinsic materials challenges, but are limited mainly due to the instability of sulfur species under electron or X-ray irradiation, and when removed from their native environment. A non-invasive in operando techniques is ideal for studying Li-S batteries. Light microscopy has been heavily used in biological science but has been paid little attention in materials science, mainly due to its lower resolution than electron microscopy. However, because of its ambient working condition, low sample damage, and different contrast mechanism, optical microscopy is ideal for studying complex and delicate materials system under real time, real environment, without radiation damage. Using optical techniques and specifically designed transparent cells, we have discovered new metastable species in operating Li-S batteries, and provided direct evidence on the debated reaction mechanism. The newly elucidated mechanism is correlated to the performance of the battery as well. This light microscopy technique could also be powerful in studying other high-energy batteries with delicate/complex electrochemistry.
ES2.12: Supercapacitors
Session Chairs
Matthew McDowell
Mauro Pasta
Friday PM, April 21, 2017
PCC North, 200 Level, Room 224 A
11:30 AM - ES2.12.01
High Energy Hybrid Supercapacitor with Asymmetrical Configuration
Fang Dai 1 , Bing Li 2 , Qiangfeng Xiao 1 , Li Yang 1 , Cunman Zhang 2 , Mei Cai 1
1 , General Motors, Warren, Michigan, United States, 2 , Tongji University, Shanghai China
Show AbstractDevelopment of novel energy storage systems that can provide higher energy and power than traditional systems is highly demanded due to the rapid growing commercial electrical device market. Among many electrochemical energy storage systems, supercapacitor has been recognized as promising system for power-based applications. Comparing with traditional dielectric capacitors, supercapacitors can provide higher energy density while maintaining the high power output. However, the energy-to-power ratio of current supercapacitors is still low comparing with other systems. Recently, a hybrid design which utilized traditional capacitor electrode as one electrode and LIB electrode as counter electrode has been demonstrated providing much higher energy density than traditional cell design.
Here we would like to present a summary of our recent investigation on hybrid type supercapacitor that shows much improved energy-to-power ratio. Different carbon based materials including commercial and lab-made samples were evaluated for their electrochemical performance. Si-based materials which were also after screening work were utilized as the counter electrode for the asymmetrical cell configuration. The optimized supercapacitor device can deliver a high material level energy density of 230 Whkg-1 at 1747 Wkg-1, which remains of 141 Whkg-1 even when power density elevated to 30127 Wkg-1. Besides the material, we’ll also share some principles for the active material screening, electrode fabrication and cell design to achieve better electrochemical performance.
11:45 AM - ES2.12.03
Ultralight, Binder Free, Freestanding, and Multi-Level Porous Graphite/Mn3O4 Electrodes for High Performance Flexible Supercapacitors
Weigu Li 1 , Xiaobin Xu 1 2 , Jing Ning 1 3 , Jianhe Guo 1 , Donglei (Emma) Fan 1
1 , The University of Texas at Austin, Austin, Texas, United States, 2 , University of California at Los Angeles, Los Angeles, California, United States, 3 , Xidian University, Xi'an, Shanxi, China
Show AbstractFreestanding, ultralight, and multi-level porous graphite foams (GMP) are designed and fabricated by using engineered multi-level porous Cu-Ni foams as templates. The multi-level porous GMP shows much enhanced electric conductivity and specific surface areas over the commonly studied ultrathin graphite foams with single-level porosity (GSP) made from Ni foams. When applied as electrode support of Mn3O4 supercapacitors, where ultrafine Mn3O4 nanocrystals are grown on the surface of graphite foam, the specific capacitance can reach ~800 F/g and 260 F/g at 1 mV/s based on the weight of Mn3O4 and entire weight of the GMP/Mn3O4 electrode, respectively. The galvanostatic life time test also shows a high capacitance retention at 90% after 10,000 cycles at 10 A/g. The fundamental mechanism of the high performance of the GMP/Mn3O4 supercapacitors is investigated. The advantageous GMP electrode materials can find broad applications in energy devices.
12:00 PM - ES2.12.04
Laser Processed 2D Transition Metal Carbides (MXenes) for Flexible Pseudo Supercapacitors
Xining Zang 1 2 , Minsong Wei 1 2 , Wenshu Chen 3 , Jiajun Gu 3 , Liwei Lin 1 2
1 , Berkeley Sensor and Actuator Center, Berkeley, California, United States, 2 Mechanical Engineering, University of California Berkley, Berkeley, California, United States, 3 Material Science Department, Shanghai Jiao Tong University, Shanghai China
Show Abstract2D meta carbide materials is recently getting great attention due to their exceptional energy capacity and durability in harsh environment with high temperature and pressure. In this paper, we develop a novel method to direct convert polymer precursors into 2D metal carbides by IR laser. The flake thickness of each metal carbide layer varies from 10nm to 100 nm. Conductivity is modified to ~50 Ω/cm2 with higher concentration of Mo5+ ions and the specific capacitance is popped up to (we need our best number here, use the unit of per g). In addition, we spincoat the polymer onto PI type to induce a ultra-thin buffer layer of graphene to “glue” the molybdenum carbides onto flexible substrate. Specific capacity is ~100mF/cm2, which is 10 times higher than laser induced graphene. The adhesion is greatly improved so that the conductivity remains after washing the electrodes in flowing water. Such direct write robust flexible electrodes with 2D metal carbide has potential application in printing electronics, energy storage especially in harsh environment. Temperature test shows that carbide based supercapacitor works stability from -50 oC to +300 oC. Specific capacitance maintain >70% at lower temperature, while up to 120 oC specific capacitance is popped up twice due to the improved activity of electrolyte.
12:15 PM - ES2.12.05
Facile Synthesis of N-Doped Porous Carbons by ZnCl2 Activation of Inexpensive Organic Building Blocks and Their Performance as Supercapacitor
Babak Ashourirad 1 , Muslum Demir 1 , Ram Gupta 1 , Hani El-Kaderi 1
1 , Virginia Commonwealth University, Richmond, Virginia, United States
Show AbstractNumerous research works have been devoted to fabrication of activated carbons and their application in energy conversion and storage during last decade. The electronic properties of plain carbons can be further modified by doping heteroatoms. Nitrogen is the most frequently studied dopant due to its versatility, availability and ease of incorporation methods into the carbon frameworks. Nitrogen-doped porous carbons can be synthesized by appropriate selection of precursors for carbon and nitrogen followed by carbonization and/or activation process at elevated temperatures. N-doped porous carbons as electrodes for supercapacitor (SC) are regarded as promising energy storage application materials, owing to their high conductivity, large surface area and controllable pores texture. Additionally, nitrogen functionalities on the surface of porous carbon contribute more positively to the total capacitance by inducing reversible faradaic redox reactions in which charge is stored through surface reactions.
The supercapacitor materials require high conductivity and high degree of graphitization. Although KOH activation yields very high surface area, the high amount of oxygen remains in the framework of carbon increases the resistivity. To address this problem a new strategy was adopted by employing ZnCl2 as activating agent and setting the higher temperatures for activation/carbonization. Benzimidazole (BI) was also selected as a single-source precursor of both carbon and nitrogen. After physical mixing of BI and ZnCl2, the formation of a stable complex takes place at early stages of heat treatment. This step is crucial since it prevents the sublimation/evaporation of organic precursor by forming molten complex. At higher temperatures, the excess ZnCl2 present in the mixture will decompose and generate gas to blow the melt and develop porosity. Accordingly, four representative samples were prepared by changing the activation temperature (700, 800, 900 and 1000 °C) and keeping the activator to precursor constant (ZnCl2/BI=2). The resultant carbons featured high surface area, appropriate micropore size distribution and various nitrogen functionalities. The CV profiles demonstrated a nearly rectangular shape and reversible humps for all electrodes that are responsible for electric double-layer capacitance (EDLC) and reversible redox transformation of N functionalities (pseudocapacitance), respectively. The highest capacitance of 330 F g–1 (at 1 A g–1 and 1 M H2SO4 as electrolyte) can be ascribed to the cooperative effects of optimal nitrogen content (10 wt%) and the surface area (870 m2 g–1) for the sample synthesize at 900 °C.
12:30 PM - ES2.12.06
Synthesis of Nitrogen-Rich Nanotubes and Utilization to Lithium and Sodium Ion Hybrid Full-Cell Capacitors Enabling High Energy and Power Densities over Robust Cycle Life
Jong Ho Won 1 , Jeung Ku Kang 1
1 Graduate School of EEWS, KAIST, Deajeon, SE, Korea (the Republic of)
Show AbstractArising from demand of high performance energy storage for the next generation devices, a hybrid capacitor is one of the great candidates to give high energy density, but its low energy density in a full-cell device is still limited for many applications. We report a lithium and sodium ion hybrid full-cell capacitor assembled by synthesis of the novel nitrogen-rich nanotubes (NRTs) with open mesoporous channels to their internal compartments using both hard and soft template-based processes, where the NRT has been employed as the cathode electrode material and the Sn encapsulated NRT as the anode electrode material.
The external morphology for the NRT was controlled using a hard template whereas the internal compartments with open mesoporous channels were created via the Rayleigh instability transform using a soft template. The unique properties of the NRT can be summarized as follows: 1) the NRT contains open mesoporous channels enabling easy penetration of electrochemical ion carriers between the electrolyte and active sites inside of its internal compartments, 2) ultrafine nanocrystals can be encapsulated inside the interior parts of the NRT, which establishes high specific capacity over a long cycle life of repeated charge/discharge cycles, 3) the heterogeneous N atoms in the carbon matrix in the NRT lead to enhanced electrochemical ion sorption/desorption during repeated redox cycles, and 4) the bare NRT and its metal encapsulated NRT are compatible to realize anode and cathode electrodes for a LHC in the full-cell configuration.
The Sn metal and NRT composites (Sn@NRT) are shown to give the high capacity at a high current density of 12 A g-1, which is also an appropriate scan rate for testing the full-cell configuration combined with the capacitor-type cathode material. Also, the NRTs, having many open mesoporous channels thus facilitating the accessibility of anion ions inside of a 1D channel, were employed for fabrication of the cathode electrode to achieve the high capacity, which is 3-folds higher than that of the commercial AC. Indeed, conjugation of the NRT and metal encapsulated NRT as the cathode and the anode materials is proven to give the high-level operation voltage and the excellent capacity retention of charge carriers in a Sn@NRT||NRT full-cell device, thus showing high energy density along with excellent power density and fast rate capability over a long cycle life.
This hybrid full-cell capacitor (Sn@NRT||NRT) is proven to show the high energy density of 274 to 127 Wh kg-1, exceeding the energy density of even a supercapacitor by more than 10-folds, at a power density of 153 to 22,800 W kg-1 along with fast rate capability and robust capacity retention over 3000 discharge/charge cycles.
ES2.13: Other Battery Materials and Systems
Session Chairs
Friday PM, April 21, 2017
PCC North, 200 Level, Room 224 A
2:30 PM - ES2.13.02
Low-Cost and High Energy Density Cathode Materials for Sodium Metal Halide Battery Applications
Guosheng Li 1 , Hee Jung Chang 1 , Keeyoung Jung 2 , Vincent Sprenkle 1
1 , Pacific Northwest National Laboratory, Richland, Washington, United States, 2 Materials Research Division, Research Institute of Industrial Science & Technology (RIST), Pohang Korea (the Republic of)
Show Abstract
Stationary electric energy storage has been considered as one of the most attractive systems, which are crucial to stimulate the growth of renewable energy resources and to improve the reliability of electric power grids. Of the particular interest is sodium-metal halide (Na-MH) battery, which has gained increasing interests as a large-scale energy storage device owing to its several advantages such as higher voltage, long cycle life, safe cell failure mode, and easiness of assembly in discharged state. Our researches at PNNL have been primary focused on developing advanced Na-MH battery technologies by lowering the operating temperature less than 200°C and adopting low cost cathode materials. In here, we will present a novel low cost and high energy density cathode materials along with detailed results of cell performances and characterizations.
2:45 PM - ES2.13.03
Atomic Layer Deposition Solid Electrolyte Enables Highly Reversible Advanced Composite FeOF Electrodes—The Mechanism for Superior Reversibility
Chuan-Fu Lin 1 , Malachi Noked 2 , Alexander Pearse 1 , Keith Gregorczyk 1 , Xiulin Fan 3 , Chunsheng Wang 3 , Gary Rubloff 1
1 Materials Science and Engineering, University of Maryland, College Park,, Maryland, United States, 2 Chemistry, Bar Ilan University, Ramat Gan Israel, 3 Chemical Engineering, University of Maryland, College Park, Maryland, United States
Show AbstractTo meet the demand for higher capacity, longer life batteries in a “next-generation batteries” technology, advanced electrodes with substantially higher energy density than current electrodes are needed. We have demonstrated the development of ALD solid electrolyte (LiPON) and the benefits of applying a controlled thin ALD layer and solid electrolyte (LiPON) as protective layers for Li and Na anodes as well as on precision-nanostructured conversion materials. [Ref:1-3]
Here in this work, we demonstrate a turn to composite electrodes formed from micro/nano size particles typical of today’s battery electrodes. We use atomic layer deposition (ALD) to create highly controlled, thin protective layers on composite FeOF conversion electrodes, testing their efficacy by cycling in batteries. ALD protection layers, the solid-electrolyte LiPON (lithium-phosphous oxynitride), were directly deposited on the electrodes in controlled inert ambient conditions. The porous structure of composite materials allows vapor-phase ALD techniques to penetrate into electrodes to form effective protection layer. We observed that the ALD protected composite conversion electrode exhibits superior cyclability (capacity retention) and high energy (round-trip) efficiency, with decreased overpotentials.
Detailed investigation was further performed to understand the mechanisms of superior reversibility for ALD protected composite electrodes, and surprisingly, based on solid-state NMR and electrochemical analysis, we observed that the ALD protection layer allows extra Li insertion to form an extended insertion-like phase for Li storage, which largely increases the capacity for highly reversible insertion regime before it turns into conversion phase transformation. This observation provides a new insight on protection layer altering the phase diagram during Li insertion, and provides technological impact on utilizing high capacity conversion electrode.
Ref:
A. C. Kozen, C.-F. Lin, A. J. Pearse, M. A. Schroeder, X. Han, L. Hu, S. B. Lee, G. W. Rubloff, and M. Noked, “Next-Generation Lithium Metal Anode Engineering via Atomic Layer Deposition,” ACS Nano, vol. 9, no. 6, pp. 5884–5892, Jun. 2015. DOI: 10.1021/acsnano.5b02166.
W. Luo, C-F Lin, O. Zhao, M. Noked, Y. Zhang, G.W. Rubloff, L. Hu, “Ultrathin Surface Coating Enables Stable Sodium Metal Anode”, Adv. Energy Mater.
C-F Lin, M. Noked, A.C. Kozen, C. Liu, O. Zhao, K. Gregorczyk, L. Hu, S.B. Lee, G.W. Rubloff, “Solid Electrolyte Lithium Phosphorous Oxynitride as a Protective Nanocladding Layer for 3D High-Capacity Conversion Electrodes”, ACS Nano, vol. 10, no. 2, pp 2693-2701 (2016). DOI:10.1021/acsnano.5b07757
3:00 PM - ES2.13.04
Are Electrospun Carbon/Metal Oxide Composite Fibers Relevant Electrode Materials for Li-Ion Batteries?
Saveria Santangelo 1 , Fabiola Panto 2 , Yafei Fan 3 , Patrizia Frontera 1 , Sara Stelitano 4 , Pier Antonucci 1 , Nicola Pinna 3
1 , Mediterranea University, DICEAM, Reggio Calabria Italy, 2 , Mediterranea University, DIIES, Reggio Calabria Italy, 3 , Humboldt-Universität zu Berlin, Institut für Chemie, Berlin Germany, 4 , Università della Calabria, DF, Arcavacata di Rende Italy
Show AbstractA large amount of studies were recently published on electrospun carbon nanofibers containing metal oxide nanoparticles (NPs) for applications in Li-ion batteries (LIBs) cf. for example Refs. [1,2]. Superior electrochemical performances of these composite materials were frequently claimed.
This study tries to make a critical assessment of the “promising” properties of electrospun electrode membranes, consisting of electroactive metal oxide NPs embedded within the three-dimensional network of carbon fibers. This is accomplished by considering the case of cobalt oxide as an example, and preparing self-standing and flexible paper-like electrodes constituted of Co3O4 NPs encapsulated in nitrogen-doped graphite-like carbon fibers.
Electrospun self-standing flexible and electrically conductive paper-like Co3O4-based fibrous membranes to be used as anodes in flexible LIBs were obtained by carefully optimizing the synthesis and post-synthesis annealing conditions.
The results of the electrochemical test carried out on Li-ion half-cells, using the membrane fabricated under optimized conditions as a self-standing negative electrode, demonstrate that it can only sustain multiple charge-discharge cycles at specific capacities around 500 mAh/g.
Moreover, the most relevant result of the present study is that the electrochemical properties of a physical mixture of cobalt oxide NPs and electrospun carbon nanofibers are equivalent to the ones of the electrospun nanocomposites, proving that the benefit of electrospun metal oxide-carbon nanocomposites is indeed limited. This study also points out that the “enhanced properties” often claimed for novel nanostructured materials for energy storage and conversion applications often arise from imprudent comparisons.
[1] M. Zhang, E. Uchaker, S. Hu, Q. Zhang, T. Wang, G. Cao, J. Li, Nanoscale, 2013, 5, 12342
[2] L. Ji, O. Toprakci, M. Alcoutlabi,Y. Yao, Y. Li, S. Zhang, B. Guo, Z. Lin, X. Zhang, ACS Appl. Mater. Interfaces 2012, 4, 2672.
3:15 PM - ES2.13.05
Ultra-Fast Energy Storage Properties of Conjugated Redox Polymers—A Mechanism Study
Fang Hao 1 , Yanliang Liang 1 , Antonio Facchetti 2 , Yan Yao 1
1 , University of Houston, Houston, Texas, United States, 2 , Northwestern University, Evanston, Illinois, United States
Show AbstractLightweight, flexible, and wearable batteries are receiving active research attention in recent years. Organic polymers are among the most suitable materials for this application as being intrinsically flexible, non-toxic, and potentially inexpensive. Organic polymer electrode materials, especially n-type cation-storing ones, traditionally had poor stability, low capacity, and slow electrode kinetics. We have recently reported π-conjugated redox polymers with high cycling stability, high capacity utilization, and ultra-fast energy storage capability (Liang et al., J. Am. Chem. Soc., 2015, 137, 4956). The polymer electrodes deliver 80% of its theoretical capacity at a rate of 50C even with a high active mass ratio of 80 wt.%, which is unusually high for organic electrode materials. There is no established theory as for how such performance can be achieved and optimized via molecular design and microstructure engineering. We set out to scrutinize the charge storage mechanism of conjugated redox polymers and investigate the influence of molecular electronic structure and electrode microstructure on electrochemical performance. We have designed and synthesized a series of polymers with largely similar structure but varying degree of conjugation in the backbone. The polymers are evaluated as positive electrode materials for rechargeable Li cells. The morphology, redox reaction kinetics, electron conductivity, and ion transport of the polymers are measured and correlated to the cell performance. It is found that the identical functional groups in these polymers ensure that regardless of the degree of conjugation, the redox reaction of the polymers proceed at similar rates, and the ion diffusion in the bulk material also happens at comparable rates. The electronic conductivity of the electrochemically reduced polymers increases by 100-fold as the π-conjugation degree of the polymers increases, agreeing with our previous observation based upon chemically doped polymers. The π-conjugation degree of the molecular structures also determines the structural order and the micromorphology of the polymers. The electrochemical surface area of the polymer electrode is continuously altered by the π-conjugation degree, which in turn impacts the ion diffusion model in the electrode. This study elucidates the underlying mechanism of charge storage in polymer electrode materials and provides guidance for further advancing these materials high-energy/power energy storage applications.
3:30 PM - ES2.13.06
Arylene Diimide Frameworks for Energy Storage
Tyler Schon 1 , Andrew Tilley 1 , Emily Kynaston 1 , Dwight Seferos 1
1 , University of Toronto, Toronto, Ontario, Canada
Show AbstractHigh performance and sustainable energy storage is desperately needed for a diverse set of applications ranging from grid-scale storage for on demand electricity needs to electronics such as sensors and radio-frequency identification (RFID) tags. Organic materials are promising candidates for battery materials on all scales due to their high abundance, high capacity, and tunable electronics. Specifically, arylene diimides have been identified as promising cathode materials because of their low cost, due to widespread use in the pigment industry, and their ability to reversibly accept multiple electrons. However, their cycling stability is limited due to their tendency to dissolve in polar organic electrolytes. Three-dimension covalent organic frameworks (COFs) are attractive architectures that incorporate the redox activity of small molecule organics into an insoluble and permanently porous framework. We have previously shown that this strategy can be applied to a thiophene-based COF that exhibits high stability as a supercapacitor material. In this work, we demonstrate the extension of this methodology to triptycene-based arylene diimide frameworks and their applications as cathode materials. Trends observed by varying the aromatic linker and the effect on performance will be discussed.
3:45 PM - ES2.13.07
Polyol Synthesis of Na2FePO4F Nanoparticles for High Rate Na-Ion Cathodes
Jesse Ko 1 3 , Vicky Doan-Nguyen 2 , Hyungseok Kim 3 , Xavier Petrissans 3 , Ryan Deblock 3 , Christopher Choi 3 , Bruce Dunn 3
1 , Naval Research Laboratory, Washington, District of Columbia, United States, 3 Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California, United States, 2 Materials Science and Engineering, University of California, Santa Barbara, Santa Barbara, California, United States
Show AbstractResearch on Na-ion batteries (NIBs) has gained momentum since sodium is relatively more earth-abundant, less expensive, and has similar intercalation chemistry to that of lithium. Phosphate-based compounds are considered to be very attractive candidates due to their thermal stability and higher voltages, which is attributed to the inductive effect of the phosphate or fluorophosphate anion. Recent studies have shown that theoretical capacities (124 mAh g-1) of sodium iron fluorophosphate (Na2FePO4F) can be achieved at slow rates. However, we lack an understanding of the kinetic behavior of Na2FePO4F. In this study, we examined the question of charge storage kinetics using nanoparticles which effectively reduce ion-diffusion path lengths. We used the polyol process to synthesize phase-pure Na2FePO4F nanoparticles. The polyol process is advantageous due to higher solubilities and chelating properties of the metal salt precursors in mild reducing conditions. The resulting Na2FePO4F nanoparticles were combined with reduced graphene oxide to improve electrical conductivities. The enhancement of the charge-storage kinetic properties of Na2FePO4F was indicated by electrochemical measurements which showed that nanoparticles lead to capacitor-like responses in contrast to the diffusion-limited mechanism exhibited by larger particles. The materials were examined for both their high-rate capability as well as high capacity. Specific gravimetric capacities between 110 mAh g-1 and 60 mAh g-1 were obtained for cycling between C/10 and 20C.
4:00 PM - ES2.13.08
The Influence of Large Cations on the Electrochemical Properties of Tunnel-Structured Metal Oxides
Yifei Yuan 1 2 , Chun Zhan 2 , Kun He 1 , Hungru Chen 3 , Khalil Amine 2 , Muhammed Islam 3 , Jun Lu 2 , Reza Shahbazian-Yassar 1
1 , University of Illinois at Chicago, Chicago, Illinois, United States, 2 , Argonne National Laboratory, Argonne, Illinois, United States, 3 , University of Bath, Bath United Kingdom
Show AbstractMetal oxides with a tunnel structure such as MnO2 are attractive as charge storage materials for rechargeable batteries and supercapacitors, since the tunnels enable fast reversible insertion/extraction of charge carriers (e.g., lithium ions). Common hydrothermal synthesis methods generally introduce large cations such as potassium, barium and ammonium ions into the tunnels, but how these cations affect charge storage performance during battery cycling is not fully understood. Here we report the role of tunnel cations in governing the electrochemical properties of electrode materials by focusing on potassium ions in alpha manganese dioxide that possesses a typical one dimensional tunnel structure. We show that the presence of cations inside 2×2 tunnels of manganese dioxide increases the electronic conductivity of the host by generating more Mn3+/Mn4+ pairs as electron hoping pathway. In addition, the presence of cations also improves lithium ion diffusivity by tuning the electronic conductivity as well as enlarging the tunnel openings for lithium ion diffusion. Transmission electron microscopy analysis indicates that the tunnels remain intact whether cations are present in the tunnels or not. When nanostructured MnO2 is tested as a cathode material in lithium ion battery, the presence of large cations in the tunnels greatly improves the rate performance of the battery, especially under the high rate condition. The superior rate performance is explained by the improved electronic conductivity and the improved lithium ion diffusivity resulted from the presence of large cations in the tunnels. These enhancements facilitate favorable electrode kinetics, and thus result in good rate performance of Li/α-MnO2 based batteries.
The results of our systematic study provide a valuable framework for the rational selection of tunnel cations and their concentrations to improve the rate performance of tunnel-based intercalation electrodes. In addition, the positive effect of potassium incorporation suggests that further exploration of tunnel-based cathodes with new battery chemistries based on Na+, Mg2+, and Al3+ ions is also warranted.