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 AM, 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
Wednesday PM, April 19, 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