9:30 AM - EE5.6.01
Investigations of Transition Metal Oxides (MnOx, Co3O4, RuO2) for Lithium Oxygen Battery Cathodes with DEMS
Dahyun Oh 1,Loza Tadesse 1,Leslie Thompson 1,Ho-Cheol Kim 1,Donald Bethune 1
1 IBM San Jose United States,2 Minnesota State University Moorhead Moorhead United States,1 IBM San Jose United StatesShow Abstract
Transition metal oxides (TMO) have been reported to have a catalytic effect on the oxygen evolution reaction in aprotic Li-oxygen batteries, resulting in lowered charging overpotentials and increased cycling lives. Here, we were able to unravel the role of three TMO’s (MnOx, Co3O4 and RuO2) in the oxidation of Li2O2 using Differential Electrochemical Mass Spectrometry (DEMS). MnOx, Co3O4 and RuO2 particles, synthesized without using any templates, surfactants or ligands, were incorporated in cathodes of Li-oxygen batteries operated with 1 M LiTFSI DME electrolyte to investigate their electrochemical functionalities. First, using our DEMS instrument, we could evaluate the oxygen recovery-to-consumption ratio (OER/ORR efficiency), and relate it to the galvanostatic profile obtained over an electrochemical cycle. In addition, linear sweep voltammetry coupled with mass spectrometry clearly showed two distinguished oxygen evolution stages and how these stages varied with TMO cathodes in charging Li-oxygen batteries. Second, the origin of decomposition of DME in the presence of these TMO’s was studied by discharging cells with 13C based TMO cathodes in an 18O2 environment. The combination of electrochemical and mass spectrometric data allowed us to determine the exact contribution of the TMO cathodes to the ORR and OER reactions. We believe that these results provide a useful guidance for selecting high performance cathode materials by considering all necessary aspects for next generation, high energy density, Li-oxygen batteries.
11:00 AM - *EE5.7.01
Challenges in Mg Battery
John Muldoon 1,Claudiu Bucur 1
1 Toyota Research Institute of N. America Ann Arbor United States,Show Abstract
Without a doubt the Holy Grail of battery research is the development of a post lithium ion technology. This may require a shift towards batteries containing a pure metal anode. Li metal is an attractive metal anode in part due to its high volumetric capacity (2062 mAh cm-3), a high reductive potential of -3.0 V vs. NHE and the wide availability of lithium electrolytes. However, its deposition occurs unevenly with formation of dendrites which leads to safety concerns during cycling. In contrast to lithium metal, magnesium metal deposition is not plagued by dendritic formation. Additionally, magnesium is more stable than lithium when exposed to air, more abundant in the earth crust and provides a higher volumetric capacity (3832 mAh cm-3). However, magnesium has a reductive potential of -2.36 V vs. NHE and has a unique electrochemistry which prohibited the use of magnesium analogues of lithium electrolytes. Since the oxidative stability of electrolytes governs the choice of cathodes it is of paramount importance to develop non-corrosive magnesium electrolyte with wide electrochemical windows which will permit discovery of high voltage cathodes. In this talk we will present the latest developments and future challenges which must be overcome.1,2,3,4,5,6
1. Aurbach, D., Lu, Z., Schechter, A., Gofer, Y., Gizbar, H., Turgeman, R., Cohen, Y., Moshkovich, M. and Levi, E., Nature, 2000, 407, 724-727.
2. Kim, H.S., Arthur, T.S., Allred, G.D., Zajicek, J., Newman, J.G., Rodnyansky, A.E., Oliver, A.G., Boggess, W.C. and Muldoon, J., Nat. Commun., 2011, 2, 427.
3. Muldoon, J., Bucur, C.B., Oliver, A.G., Sugimoto, T., Matsui, M., Kim, H.S., Allred, G.D., Zajicek, J. and Kotani, Y., Energy Environ. Sci., 2012, 5, 5941-5950.
4. Muldoon, J., Bucur, C.B., Oliver, A.G., Zajicek, J., Allred, G.D and Boggess, W.C. Energy Environ. Sci, 2013, 6, 482-487.
5. Muldoon, J., Bucur, C.B. and Gregory. T. Chem. Rev., 2014, 114, 11683-11720
6. Muldoon, J., Bucur, C.B. and Gregory. T. Phys. Chem. Lett., 2015, 6, 3578–3591
11:30 AM - EE5.7.02
Trends in Ligand Modification for Magnesium-Ion Electrolyte Improvement
Carl Nist-Lund 1,Jake Herb 1,Craig Arnold 1
1 Princeton University Princeton United States,Show Abstract
Nonaqueous magnesium-ion battery research has been growing due to the attractive characteristics of such systems, including a high theoretical energy density and, compared to lithium-ion systems, a relatively low cost of materials. Increasing the electronegativity of precursor ligands is an important trend in enhancing the oxidative stability of electrolytes, and thus can enable the use of higher voltage cathode materials.1,2
We have performed electrochemical analysis on a series of solutions made from various magnesium alkoxide and aryloxide compounds in combination with AlCl3 in ethereal solvents. Displaying comparable electrochemical windows, deposition efficiencies, and conductivities compared to previously researched systems, these compounds show a high degree of promise. Additionally, these free flowing alkoxide powder precursors are significantly easier to handle compared to traditional Grignard-based and amido-based magnesium electrolyte precursors. Our work seeks to more fully understand these trends and materials. The synthesis and electrochemical behavior of a series of magnesium alkoxide and aryloxide salts were prepared as precursors for electrolytes for magnesium-ion batteries, and analyzed using cyclic voltammetry and coin-cell measurements.
1. Yoo, H. D.; Shterenberg, I.; Gofer, Y.; Gershinsky, G.; Pour, N.; Aurbach, D.Energy Environ. Sci. 2013, 6, 2265.
2. Nelson, E. G.; Kampf, J. W.; Bartlett, B. M. Chem. Commun. (Camb). 2014, 50, 5193–5195.
11:45 AM - EE5.7.03
Pyrite (FeS2) Nanocrystals as Electrode Material for Sodium-Ion and Sodium/Magnesium-Ion Hybrid Batteries
Marc Walter 1,Tanja Zuend 1,Kostiantyn Kravchyk 1,Maria Ibanez 1,Maksym Kovalenko 1
2 Laboratory of Inorganic Chemistry ETH Zurich Zurich Switzerland,1 Empa - Swiss Federal Laboratories for Materials Science and Technology Dübendorf Switzerland,Show Abstract
Lithium-ion batteries (LIBs) are nowadays the predominant battery technology for portable electronics and are of growing importance in the area of electrical mobility. However, the limited abundance and uneven global distribution of lithium salts are raising concerns regarding future price development and supply security. In this regard, Sodium-ion batteries (SIBs) are gaining increasing attention as more economical alternative, due to the ubiquitous nature of sodium salts. However, especially due to the ~50% larger ionic radius of the Na-ion the electrochemistry of SIBs and LIBs is generally very different and the development of new materials is essential in this field. In fact, many alloying and conversion materials are considered promising candidates as electrode materials for SIBs based on their high specific and volumetric capacities. However, these materials undergo drastic volume changes leading to rapid capacity fading after only a few cycles. In this regard, nanocrystals (NCs) are advantageous electrode materials, since they can improve the cycling stability by mitigating the impact of volume changes. Moreover, as a result of the reduced dimensions and higher surface area, NCs offer faster kinetics compared to their bulk counterparts.
Due to its non-toxicity, low raw material cost and high storage capacity FeS2 so far has been only considered as promising cathode material for LIBs and SIBs. We demonstrate, for the first time, that FeS2 NCs can in fact serve as excellent Na-ion anode material with good cycling stability and rate capability. Namely, FeS2 NCs deliver capacities ≥500 mAhg-1 for 400 cycles at a current rate of 1000 mAg-1 clearly exceeding the performance of both bulk FeS2 as well as various other nanostructured metal sulfides.
Further, we present a hybrid intercalation battery based on a FeS2 NC cathode, metallic magnesium anode and sodium/magnesium dual salt electrolyte.  Unlike lithium or sodium, metallic magnesium can be safely used due to dendrite-free electroplating and offers high volumetric (3833 mAhcm-3) and gravimetric capacities (2205 mAhg-1). Na-ion cathodes – in particular FeS2 NCs – may serve as attractive alternatives to Mg-ion cathodes due fast, highly reversible insertion of Na-ions. In the presented proof-of-concept study, electrochemical cycling of the Na/Mg hybrid battery is characterized by high rate capability, high coulombic efficiency of 99.8% and high energy density. In particular, with an average discharge voltage of ~1.0 V and an average cathodic capacity of 189 mAhg-1 at a current of 200 mAg-1, the presented Mg/FeS2 hybrid battery delivers energy densities of up to 215 Whkg-1. Such a hybrid Na-Mg battery, fully based on Earth-abundant elements, is highly promising for future large-scale energy storage solutions.
 M. Walter, T. Zünd and M. V. Kovalenko Nanoscale, 2015, 7, 9158-9163.
 M. Walter, K. V. Kravchyk, M. Ibanez and M. V. Kovalenko, submitted.
12:00 PM - EE5.7.04
A Binder-Free V2O5 ●0.5H2O Cathode Used in Rechargeable Aluminum Battery
Huali Wang 2,Gao Liu 2,Ying Bai 1,Chuan Wu 1,Shi Chen 1,Daozhou Liu 1,Sichen Gu 1
1 Beijing Institute of Technology Beijing China,2 Lawrence Berkeley National Laboratory Berkeley United States,2 Lawrence Berkeley National Laboratory Berkeley United States1 Beijing Institute of Technology Beijing ChinaShow Abstract
Aluminum is a very attractive material for next-generation energy storage, since it is the most abundant metal in the earth’s crust. Its relatively low atomic weight of 26.98 along with its trivalence give a corresponding electrochemical equivalent of 2.98 Ah/g and a extremely high volume capacity(8.04 Ah/cm3). It is noted that the Al3+ cation has a smaller radius (53.5 pm), which may act as a guest species in intercalation chemistry. Fabrication of rechargeable aluminum battery working at room temperature did not succeed until haloaluminate containing ionic liquids were used as electrolytes. Anions of ionic liquids are expected to have a great effect on performance of rechargeable aluminum batteries. Concentration of Al2Cl7- is considered as a key factor in chloroaluminate ionic liquids when used as electrolytes. Vanadium pentoxide (V2O5) is a favorable candidate as a Na-ion and Al-ion intercalation electrode because of its layered structure, which is open to reversible metal-ion insertion/extraction. Considering acidic AlCl3 contained ionic liquids are not compatible with some binders, a binder-free cathode was synthesized by in-situ hydrothermal deposition of V2O5 on Ni foam current collector, which delivered an initial discharge capacity of 239 mAh/g. An obvious discharge voltage plateau appeared at 0.6 V in the discharge curves of the Ni-V2O5 cathode, which is slightly higher than that of the V2O5 nanowire cathodes with common binders attributing to reduced electrochemical polarization. In comparison with crystalline V2O5, the hydrated form of vanadium pentoxide (V2O5●nH2O) has good chemical stability. Due to the expended interlayer distance, large atomic and molecular species and even polymers can be reversibly intercalated between the layers of V2O5●nH2O. Therefore, it is a very promising strategy to prepare V2O5●nH2O with a particular structure on a conductive substrate, to achieve aluminum battery with good performance by enhancing charge-transfer conductivity and preserving the interface morphology integrity. A simple and clean hydrothermal approach was used for synthesizing a cathode material, consisting of V2O5●0.5H2O nanometer-thick lamella grown on stainless steel mesh. It could effectively maintain the electrode integrity during charge/discharge processes and facilitate the electronic and ionic transportation, with the help of the mechanical strength and the high porosity of the stainless steel mesh. A stabilized capacity of 110 mAh/g under a high current density of 100 mA/g was achieved at 180 cycles.
2:30 PM - EE5.8.01
Anode Architectures, Anode/Electrolyte Interfaces, and High Energy-Density Anodes for Rechargeable Magnesium Battery Systems
Nikhilendra Singh 1,Timothy Arthur 1,Fuminori Mizuno 1
1 Materials Research Department Toyota Research Institute of North America Ann Arbor United States,Show Abstract
Multivalent battery systems like rechargeable magnesium (Mg) batteries have recently gained more interest as candidate post-lithium (Li) battery systems, for possible applications in electric vehicles (EVs) and plug-in hybrid vehicles (PHVs). This is primarily due to concerns over the range performance of current Li battery systems, and the space requirements for future EVs and PHVs. Mg, being divalent and denser, is theoretically capable of delivering a higher volumetric energy-density (3833 mAh cm-3) than Li (2061 mAh cm-3), making it a viable battery system for addressing current range and space concerns.1-4 To date, various organohaloaluminate electrolytes and electrolytes containing the B-H family have been utilized in Mg batteries, due to the incompatibility of conventional battery electrolytes (TFSI-, ClO4-, PF6-) with Mg metal anodes.3,5 However, as recently reported, it is also possible to use conventional battery electrolytes for Mg-ion batteries, by changing the type of anode, from a Mg metal anode to a Mg-ion insertion-type anode. This change enables Mg-ion transport through the anode/electrolyte interface during the use of conventional battery electrolytes.2-4,6
Here, we report recent advancements in alternate architectures, as well as new materials for insertion-type anodes for rechargeable Mg-ion batteries. Further, we address specific studies related to the observation of the anode/electrolyte interface for Mg batteries, which have recently been studied in some detail.7,8 Results from the utilization of alternate architectures and recent fundamental analytical analyses, focused on studying and understanding the nature of the anode/electrolyte interface, will be presented and discussed.
1 Mizuno F, Singh N, Arthur TS, Fanson PT, Ramanathan M, Benmayza A, Prakash J, Liu Y-S, Glans P-A, Guo J, Frontiers in Energy Research, 2014, 2, 1.
2 N. Singh, T. S. Arthur, C. Ling, M. Matsui and F. Mizuno, Chem. Commun., 2013, 49, 149.
3 Muldoon J, Bucur CB, Gregory T, Chemical Reviews 2014, 114, 11683.
4 T. S. Arthur, N. Singh and M. Matsui, Electrochem. Commun., 2012, 16, 103.
5 Mohtadi R, Matsui M, Arthur TS, Hwang S-J, Angewandte Chemie International Edition 2012, 51, 1.
6 Shao Y, Gu M, Li X, Nie Z, Zuo P, Li G, Liu T, Xiao J, Cheng Y, Wang C, Zhang J-G, Liu J, Nano Letters, 2014, 14, 255.
7 T. S. Arthur, P-A. Glans, M. Matsui, R. Zhang, B. Ma and J. Guo, Electrochem. Commun., 2012, 24, 43.
8 Benmayza A, Ramanathan M, Arthur T, Matsui M, Mizuno F, Guo J, Glans P-A, Prakash J, Journal of Physical Chemistry C, 2013, 117, 26881.
3:15 PM - EE5.8.04
P-Block Elements for Rechargeable Mg System: Electrochemical Performance and Structural Characterization
Fabrizio Murgia 2,Ephrem Weldekidan 2,Lorenzo Stievano 2,Laure Monconduit 2,Romain Berthelot 2
1 Equipe Agregats Interfaces Materiaux pour lEnergie Institut Charles Gerhardt de Montpellier (UMR 5253 CNRS Unite de Montpellier) Montpellier France,2 Réseau sur le Stockage Électrochimique de l’Énergie (FR 3459 CNRS) Amiens France,Show Abstract
In order to make available the increasing amount of energy produced by clean and renewable sources at any moment and conditions, cheap, efficient and high-capacity rechargeable systems are needed. Although lithium-ion batteries (LIB) meet these requirements for many applications, the possibility that LIB fulfil the growing demand of more energy-consuming uses is nowadays called into question. Moreover, the future demand of Li seems difficult to satisfy since Li is relatively rare and not evenly distributed on Earth. A strong interest is thus given to alternative solutions and, thanks to its abundance, low price, safety features and high volumetric energy density (3837 mAh/cm3), Mg is today considered as a promising candidate for next-generation energy storage applications. However, only highly air-sensitive electrolytes are compatible with Mg metal that undergoes irreversible passivation with conventional formulations. One of the strategies to overcome this hurdle consists in replacing Mg metal with other materials able to reversibly alloy with Mg, building a veritable Mg-ion battery (MIBs), and allowing the use of safer electrolyte formulations. A few p-block elements (Sn, Sb and Bi) were identified as promising candidates for negative electrodes on MIBs. Following these leading studies, we showed that micron-sized Bi is able to reversibly alloy to Mg (372 mAh/g) even at fast current rates, undergoing a biphasic reaction with the direct formation of well-cristallized Mg3Bi2. Cell capacities recorded during c-rate tests are in line with more elaborate Bi nanotubes. Moreover, ball-milling made Mg3Bi2 was successfully tested in a complete cell and can be set as a promising candidate for next-generation of MiBs. Similar results were obtained for In, which reversibly alloys with Mg (425 mAh/g) at low c-rates exhibiting the lowest alloying voltage ever reported vs. Mg. Fast rate cycling affects the performance of In that suffers of poor kinetics. Operando XRD shows the reversible formation of crystalline MgIn.
To improve the overall performance of the negative electrodes, we recently explored the possible combination of two p-group elements, in order to profit of a synergistic effect between good performance (Bi) and high capacity (In, Sn). The study of these mixed-metal systems and of their electrochemical mechanisms vs. Mg metal, which allows us to explain the observed improvement of their performance compared to pure metals, will be highlighted in this communication.
 J.B. Goodenough, K.S. Park, J. Am. Chem. Soc. 135 (2013) 1167.
 J.-M. Tarascon, Nat. Chem. 2 (2010) 510.
 P. Novák, R. Imhof, O. Haas, Electrochim. Acta 45 (1999) 351.
 F. Murgia, L. Stievano, L. Monconduit, R. Berthelot, J. Mater. Chem. A 3 (2015) 16478.
 Y. Shao, M. Gu, X. Li, Z. Nie, P. Zuo, G. Li, T. Liu, J. Xiao, Nano Lett. 20 (2014) 255.
 F. Murgia, E.T. Weldekidan, L. Stievano, L. Monconduit, R. Berthelot, Electrochem. Commun. 60 (2015) 56.
4:30 PM - EE5.8.07
Investigation of the NaxMoO2 Phase Diagram from Sodium Electrochemical (de)Intercalation
Laura Vitoux 1,Marie Guignard 1,Francois Weill 1,Matthew Suchomel 2,Jacques Darriet 1,Claude Delmas 1
1 CNRS, Univ. Bordeaux, ICMCB, UPR 9048 Pessac France,2 Argonne National Laboratory, Advanced Photon Source Lemont United StatesShow Abstract
Research on sodium layered oxides NaxMO2 (M: 3d or 4d transition metal, x: sodium content) as positive electrode in sodium ion batteries have regained interest for stationary energy storage applications. Furthermore, due to their structure, in which sodium occupy interstitial sites (octahedral or prismatic) between [MO2] slabs constituted of MoO6 edge-sharing octahedra, sodium layered oxides can exhibit original physical properties depending on their chemical composition (nature of the transition metal and sodium content).
This work focus on NaxMoO2 layered oxides, which have been the subject of only a few publications in the 1980’s concerning Na2/3MoO2 [1-4], and Na0.5MoO2 . The only electrochemical investigation , shows a reversible sodium intercalation in NaxMoO2 for 0.28
4:45 PM - EE5.8.08
Sodium Intercalation Mechanisms into Corrugated Titanate Structures for Na-Ion Batteries
Isaac Markus 2,Mona Shirpour 2,Simon Engelke 2,Siafung Dang 3,Marco Prill 3,Robert Spatschek 3,Mark Asta 1,Marca Doeff 2
1 Material Science and Engineering UC Berkeley Berkeley United States,2 Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley United States,2 Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley United States3 IEK2 Forschungzentrum Jülich Julich Germany1 Material Science and Engineering UC Berkeley Berkeley United StatesShow Abstract
Sodium ion batteries (SIBs) are one of the most promising technologies for grid storage due to the large abundance of sodium in the earth’s crust. Grid scale storage must not only be available at a low cost but must also be based on materials that are abundant enough to cover the scale of future energy consumption. SIBs have the additional advantage that they can utilize many of the manufacturing and processing techniques used by current lithium ion batteries. However, SIBs still face challenges related to energy density given that graphite is not able to intercalate high amounts of sodium. As an alternative, sodium titanates are attractive anode materials for SIBs due to their rich range of crystal structures that can reversibly intercalate sodium ions.
In this work we investigated two types of titanates that have been recently synthesized and tested. The first is based on Na1+xTi3O6(OH)×2H2O, known as sodium nonatitanate1, and the second is based on the lepidocrocite structures, Na0.8Ti1.73Li0.27O4 and Na0.8Ti1.4Mg0.6O42. Using density functional theory (DFT) we computed the structural changes during sodiation, and calculated voltage profiles for the different materials. We also calculated changes to the sodium diffusion energy barriers at different sodium concentrations. Structural results indicate that sodium intercalation is a site-limited process in both sets of titanates, with energy barriers increasing during sodiation.
Experiments on the phase stability of these compounds are underway employing coulometric titration and differential scanning calorimetry. Because Na2Ti3O7 has been shown to undergo phase relaxation with increasing sodium content3, we seek to understand if other titanates are also susceptible to phase changes during sodiation. Thermal stability results indicate that for both sets of materials the pristine and sodiated structures are stable up to at least 500o C. Current efforts are focused on detecting if the materials undergo phase relaxations at discharge conditions.
1. Shirpour M., Cabana J., Doeff M. “New materials based on a layered sodium titanate for dual electrochemical Na and Li intercalation systems”, Energy Environ. Sci., 6, 2538 (2013).
2. Shirpour M., Cabana J., Doeff M. “Lepidocrocite-type Layered Titanate Structures: New Lithium and Sodium Ion Intercalation Anode Materials.” Chemistry of Materials 2014 26 (8), 2502-2512.
3. Xu J., Ma C., Balasubramanian M., Meng Y.S. “ Understanding Na2Ti3O7 as an ultra-low voltage anode material for a Na-ion battery.” Chem. Commun. 2014, 50, 12564-12567.
EE5.9: Poster Session II: Next-Generation Supercapacitor Materials and Devices
Friday AM, April 01, 2016
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - EE5.9.01
Light-Weight Nitrogen-Doped Hierarchically Porous Carbon Foam for Energy Storage Devices
Jizhang Chen 1,Ni Zhao 1,Ching-Ping Wong 2
1 Department of Electronic Engineering The Chinese University of Hong Kong Shatin, New Territories Hong Kong,1 Department of Electronic Engineering The Chinese University of Hong Kong Shatin, New Territories Hong Kong,2 School of Materials Science and Engineering Georgia Institute of Technology Atlanta United StatesShow Abstract
Free-standing three dimensional (3D) carbonaceous materials have emerged as a promising type of materials, owing to their advantages such as self-support, great flexibility and compressibility, high electronic and thermal conductivities, high chemical stability, and large amount of interconnected macropores. These materials have shown attracting performances for a variety of applications, such as electrochemical electrodes (e.g. for supercapacitors, batteries, fuel cells, and solar cells), absorbers, and matrixes for sensors and thermal energy storage. Current synthesis methods for free-standing 3-D carbon are either time-consuming and complicated or uncontrollable. In this study, we address this problem through developing a facile, scalable, and cost-effective strategy to fabricate hierarchically porous carbon foam (HP-CF) by directly annealing home-made melamine foam. The HP-CF serves as an excellent material for supercapacitors owning to its multiscale, interconnected porous morphology as well as the proper density that ensures not only a high gravimetric capacitance but also a high volumetric capacitance. Moreover, the HP-CF can be used as the current collector and mechanical matrix to support pseudocapacitive materials, so that asymmetric supercapacitors (ASC) can be assembled. In the ASCs, the 3-D interconnected hierarchically porous architecture allows for rapid and efficient ionic transport, while the continuous carbon matrix provides sufficient transport routes for electrons. As a result, the obtained ASC devices exhibit both high energy and high power. Importantly, the HP-CF is much lighter and more flexible than conventional Ni foams. All these characteristics make the HP-CF an ideal material for constructing next-generation lightweight and flexible energy storage devices.
9:00 PM - EE5.9.02
Novel Carbon Nanoscale Architectures for Supercapcitors
Guanhua Zhang 2,Huigao Duan 2,Jingyue Liu 1,Wen Zhang 1
1 Departments of Physics Arizona State University Tempe United States,2 School of Physics and Electronics Hunan University Changsha China,2 School of Physics and Electronics Hunan University Changsha China1 Departments of Physics Arizona State University Tempe United StatesShow Abstract
The fast-growing market for portable electronic devices and the development of hybrid electric vehicles leads to urgent demand for high performance energy storage systems. Supercapacitors have received considerable attention because of their high power density, fast recharge capability and long cycle life [1-2] Hierarchical carbon nanoarchitectures are strongly desirable for constructing advanced supercapacitors due to their high capacitance and good rate capability. The processes of fabricating such structures, however, are complicated, expensive, and time-consuming. We recently developed a novel synthesis approach to produce three-dimensionally patterned growth of hollow carbon nanotube arrays (CNTAs) on flexible cloth consisting of carbon fibers (CFs). The facile synthesis protocol is repeatable, scalable and easy to process. The CNTAs@CFs were directly used as integrated electrodes for supercapacitors and exhibited a high specific capacitance of 200 F/g at 20 A/g in 6 M KOH aqueous solution in three-electrode mode, and an excellent cycling ability with a 98% of the initial capacitance remained after 4000 cycles. Moreover, the capacitance still maintained a value of 182 F/g even when the current density increased to 40 A/g. These excellent electrochemical performances were ascribed to the novel structure of the porous vertical CNTAs which provide enhanced electronic and ionic transport. The CNTAs@CFs electrodes without the use of any auxiliary materials are expected to open up new opportunities for carbon-based materials to power flexible electronic devices. The design strategy, the synthesis processes and the electrochemical properties of the CNTAs@CFs will be discussed .
 Simon, Patrice, and Yury Gogotsi. Materials for electrochemical capacitors. Nature materials 7 (2008): 845-854.
 Pech, David, et al. Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon. Nature nanotechnology 5 (2010): 651-654.
 This research was funded by the College of Liberal Arts and Sciences of Arizona State University. G. Zhang acknowledges the financial support from the China Scholarship Council (CSC). The authors gratefully acknowledge the use of facilities within the LeRoy Eyring Center for Solid State Science at Arizona State University.
9:00 PM - EE5.9.03
From Lignin to a Nanoporous Carbon: How the Synthesis Steps Affect the Final Texture/Structure and the Electrochemical Properties
Adriana Navarro-Suarez 1,Damien Saurel 1,Javier Carretero-Gonzalez 2,Teofilo Rojo 3
1 CIC energiGUNE Minano Menor Spain,2 Faculty of Chemistry Warsaw University of Technology Warsaw Poland1 CIC energiGUNE Minano Menor Spain,3 Inorganic Chemistry Department University of the Basque Country Bilbao SpainShow Abstract
Batteries and supercapacitors, are of crucial importance for advanced and highly efficient energy storage and management, their complementary qualities might be used in hybrid systems which made the optimization of both materials of utmost importance.  In electrical double-layer capacitors (EDLCs), porous carbon is the most used electrode material because of its relatively low cost, high surface area and availability. Control of the textural (average pore size and surface area) and structural (graphitization, defects, etc.) properties of the carbon, has proven to be of great importance. The former, because only solvated or partially solvated ionic species that are smaller than the pores can be absorbed, even though a large porosity would imply low volumetric density and therefore low volumetric power and energy. While the latter, on the grounds that an increase in the crystal size of ordered regions in amorphous carbons has proven to be detrimental to the capacitance. [2, 3]
Nanoporous carbons with narrow and tunable pore size (~ 1 nm) and surface area (800-1600 m2/g) have been produced by chemical activation of lignin, an industrial by-product. The influence of carbonization/activation temperatures and activating agent ratio on the final textural and structural properties were evaluated. On one hand, Small Angle X-ray Scattering revealed the presence of an internal porosity in the carbonized samples that affected the final porosity on the activated ones as shown also by adsorption/desorption of N2 gas at 77 K. On the other hand, Raman Spectroscopy and Electronic Microscopy showed the effect of the KOH/Carbon on the formation of ordered regions embedded in the amorphous carbon.
Cyclic voltammetry studies, charge/discharge galvanostatic measurements and impedance experiments allowed determining the carbon with the most adapted pore size to each electrolyte as well as their effect on its capacitive properties in symmetric double-layer capacitors. Capacitances up to 200 F/g and 100 F/g in aqueous and organic electrolytes respectively were achieved. Ageing experiments were developed by using floating tests in aqueous electrolytes exhibiting an increase in the capacitance of 17% after 140 hours.
 F. Béguin, V. Presser, A. Balducci and E. Frackowiak, Adv. Mater., 2014, 26, 2219-2251.
 M. Noked, A. Soffer and D. Aurbach, J. Solid State Electrochem., 2011, 15(7), 1563-1578.
 A.M. Navarro-Suárez, J. Carretero-González, V. Roddatis, E. Goikolea, J. Ségalini, E. Redondo, T. Rojo and R. Mysyk, RSC Adv., 2014, 4, 48336-48343.
9:00 PM - EE5.9.04
Zeolite-Templated Carbons in Alkaline Electrolyte as Electric Double Layer Capacitors
Chenchen Hu 2,Alexandre Magasinski 1,Gleb Yushin 1
1 School of Materials Science and Engineering Georgia Institute of Technology Atlanta United States,2 School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan China,1 School of Materials Science and Engineering Georgia Institute of Technology Atlanta United StatesShow Abstract
Electrochemical double layer capacitors (EDLCs) have emerged as attractive energy storage devices due to their high power density and long cycle life.1 The energy is stored at the interface of electrode/electrolyte through reversible ion adsorption/desorption on high surface area carbons. Zeolite template carbons (ZTCs) first invented by Kyotani et al. 2 are promising material for both fundamental studies and practical applications of EDLCs due to their highly-ordered and well-defined micropores and large specific surface areas (SSA).3, 4 In this study, ZTCs were synthesized through a low pressure chemical vapor deposition (LPCVD) of carbon on the internal surface of a sacrificial NaY zeolite template. Optimized parameters of preparing ZTCs were systematically studied, and symmetric capacitors were assembled and tested in the series alkaline electrolyte.
Electrochemical performance of ZTCs was studied by cyclic voltammetry (CV), charge-discharge (C-D) and electrochemical impedance spectroscopy (EIS) tests in LiOH, NaOH, KOH and CsOH electrolyte solutions. The impacts of the size of the cation and solvation shell as well as its solvation energy have been systematically investigated. This presentation will discuss the substantial impacts of both the cation properties and molarity of electrolytes on their electrochemical performance in microporous carbons and will reveal the complex relationships between the size of micropores, carbon surface chemistry and electrolyte composition.
1 C. Merlet, B. Rotenberg, P. A. Madden, P.-L. Taberna, P. Simon, Y. Gogotsi and M. Salanne, On the molecular origin of supercapacitance in nanoporous carbon electrodes. Nat Mater, 11, 306-310, (2012).
2 T. Kyotani, Z. Ma and A. Tomita, Template synthesis of novel porous carbons using various types of zeolites. Carbon, 41, 1451-1459, (2003).
3 Y. Korenblit, A. Kajdos, W. C. West, M. C. Smart, E. J. Brandon, A. Kvit, J. Jagiello and G. Yushin, In Situ Studies of Ion Transport in Microporous Supercapacitor Electrodes at Ultralow Temperatures. Advanced Functional Materials, 22, 1655-1662, (2012).
4 A. Kajdos, A. Kvit, F. Jones, J. Jagiello and G. Yushin, Tailoring the Pore Alignment for Rapid Ion Transport in Microporous Carbons. Journal of the American Chemical Society, 132, 3252-3253, (2010).
9:00 PM - EE5.9.05
Polyaniline-Carbon Nanotube Composite for High Performance Pseudocapacitive Desalination
Jim Benson 1,Aaron Ranallo 1,Mark Schauer 2,Gleb Yushin 1
1 Georgia Inst of Technology Atlanta United States,2 Nanocomp Technologies Inc. Concord United StatesShow Abstract
Capacitive deionization (CDI) is a research field which has been gaining more interest as water scarcity and drought continue to worsen in areas throughout the world. Pseudocapacitive deionization is a subset of CDI which has shown a great promise due to high salt absorption capacities which exceed the capabilities of high surface area carbons alone and in conjunction with ion exchange membranes. Conductive polymers like polyaniline have been of interest in CDI for years due to its high conductivity, good environmental stability, tailorable nanostructure, and mechanical properties. Compared to other supercapacitor active materials PANI is unique in that the ion exchange process by which the polymer equilibrates with acid solutions also imposes the anion into the polymer. This has been the basis for the use of PANI as an anion exchange polymer for mixtures of halide ions such as those found in salt water and can be used for desalination applications using CDI.
Most synthesis using in situ polymerization result in poor adhesion and poor cyclability. Electrodeposition provides a better coverage and higher material utilization and doesn’t need a binder but requires a high quality substrate with good mechanical support. We were able to achieve uniform nanometer scale coatings through the bulk of these fabrics while maintaining high polymer mass loading by using a pulsed current electrodeposition method.
A CNT-based fabric was produced using a commercial-scale continuous chemical vapor deposition process that allows rapid manufacturing of high-strength CNT sheets with tunable mechanical properties. In addition to providing a platform for achieving multifunctionality, these CNT substrates also allow the elimination of non-electroactive materials such as binders and heavy foil current collectors which further increase the desalting efficiency.
When tested for CDI applications in synthetic NaCl solution and brackish groundwater samples, the composites showed rapid ion adsorption and high specific and volumetric capacitances up to 240 F●g-1 (~310 F●cm-3) in salt solutions exceeding that of state of the art activated carbon electrodes. In contrast to other PANI-containing composites, the conformal coating and CNT structural characteristics and electrical conductivity allow for a stable performance during more than 20,000 galvanostatic cycles at high current densities and in real ground water samples. The effects of varying the mass loading were also studied. Additionally, constant voltage salt adsorption experiments were performed at different adsorption times (5-30min) and voltage steps (0.6-1.2V) in beaker cell experiments. Finally salt adsorption studies will be discussed using continuous flow cell experiments in conjunction with real time solution conductivity measurements.
9:00 PM - EE5.9.06
Mesoporous Hollow Carbon Nanofibers for Supercapacitors
Yian Song 1,Guanhua Zhang 1,Jingyue Liu 1
1 Arizona State University Tempe United States,Show Abstract
Supercapacitors, due to their high power density and the ability to bridge the gap between conventional capacitors and batteries, have recently attracted much attention . The goal of developing supercapacitors is to increase their energy density, reduce their charge time, and extend their lifetime. It is desirable to design and synthesize porous hollow carbon nanostructures with large specific surface area and appropriate pore sizes for transport of ions or ion complexes while maintaining excellent electrical conductivity. The use of hollow nanostructures is presumed to provide “ion buffering” reservoirs which can expedite the charge and discharge processes . Excellent electrical conductivity requires highly graphitized carbon and conducting channels for electron transport. High-surface area and large pores, however, may decrease the electrical conductivity of the system. Therefore, there may exist delicate structural balances to optimize both the electrical and ionic conductivity for better supercapacitor systems. We have used ZnO nanowires as sacrificial templates to synthesize porous hollow carbon nanofibers. Since the diameter/length of the ZnO nanowires can be tuned, the effects of the inner diameter/length of the carbon nanofibers on the performances of the supercapacitors can be evaluated. Furthermore, because of the catalytic properties of the ZnO nanowires both ethanol decomposition and steam reforming reaction occur on the ZnO surface, leaving a layer of carbonaceous species uniformly coated on the ZnO nanowires. Thermal treatment to remove the ZnO nanowires results in porous hollow carbon nanofibers and by controlling the thickness of the coating layer porous carbon nanofibers with controllable wall thicknesses can be synthesized. Initial results demonstrated that high surface area (>1100 m2/g) and large specific capacitance (>220 F/g at 1A/g current density) could be obtained .
 Simon, P.; Gogotsi, Y. Nat Mater 2008, 7, 845-854.
 You, B.; Yang, J.; Sun, Y. Q.; Su, Q. D. Chemical Communications 2011, 47, 12364-12366.
 The authors acknowledge funding by the College of the Liberal Arts and Science of Arizona State University and the use of facilities in the John M. Cowley Center for High Resolution Electron Microscopy at Arizona State University. We appreciate the assistance of Mr. Daniel Mieritz and Dr. Don Seo for surface area measurement.
9:00 PM - EE5.9.07
Large-Scale Fabrication of Three-Dimensional Carbon Based Materials for Supercapacitors
Minghao Yu 1,Yinxiang Zeng 1,Yexiang Tong 1,Xihong Lu 1
1 Sun Yat-Sen Univ Guangzhou China,Show Abstract
Three-dimensional graphene based materials (3DGs) are emerging as a new class of electrode materials for Supercapacitors because of its unique structure and fascinating properties.However, most of the developed approaches for preparing 3DGs require high production cost, high temperature, and/or complicated manipulation and instrumentations, which are still not satisfactory for large-scale production of 3DGs in low cost. Recently, we demonstrated for the first time that the use of commercial graphite paper (GP) to massively prepare macroscopically porous 3DGs by combining the modified Hummer's method with a freezing technique. Compared with recently reported strategies for producing 3D graphene, the present method has significant advantages of simpleness, time- and energy-saving, low cost and suitable for massive production. The as-prepared 3DGs that consisted of well exfoliated, high-quality reduced graphene oxide (RGO) exhibited meso-porous structure and superior conductivity. When used as scaffold for PANI, the PANI/3DGs composite electrode yielded a highest specific capacitance of 596.1 F g−1 at a current of 2 mA, which is considerably higher than the values in recent reports for PANI electrodes. In addition, we also developed a new one-step electrochemical activation strategy to distinctly boost the capacitive properties of the commercial carbon cloth (CC) under mild conditions and their implementation as high-performance anodes for asymmetric supercapacitors (ASCs). The electrochemically activated CC (EACC) electrode reached an impressive areal capacitance of 756 mF cm−2 at a high current density of 6 mA cm−2 with predominant cycling stability. Moreover, a flexible ASC device with a remarkable energy density of 1.5 mWh cm−3 and stable working voltage of 2 V was achieved by using the EACC electrode as anode and a MnO2@TiN electrode as cathode. Additionally, this fabricated MnO2@TiN//EACC ASC device also has excellent long-term durability without any decay of capacitive performance after 70 000 cycles.
9:00 PM - EE5.9.08
Graphene and Poly (3,4-ethylenedioxythiophene) (PEDOT) Based Hybrid Supercapacitors with Ionic Liquid Gel Electrolyte in Solid-State Design and their Electrochemical Performance in Storage of Solar Photovoltaic Generated Electricity
Amr Obeidat 2,Alok Rastogi 2
1 Electrical and Computer Engineering Binghamton University, SUNY, Binghamton Binghamton United States,2 Center for Autonomous Solar Power (CASP) Binghamton University, SUNY, Binghamton Binghamton United States,Show Abstract
Supercapacitors with high specific power, fast charging rates and long cycle life are now well recognized as potent energy/power storage devices. Energy storage in one category of supercapacitors is via ion accumulation in electrified double layers and in the other via redox processes. Graphene and carbon nanotubes boost capacitive energy by large surface area and open pore structure in double layer capacitors. Redox pseudocapacitors are based on PEDOT, polyaniline or polypyrrole, conducting polymers and transition metal oxides. Extensive research is required to bridge the technology gap in attaining high energy density capability comparable to that of rechargeable batteries. In this context, hybrid supercapacitors which utilize one double layer and the other pesudocapacitive electrode function over high potentials to boost energy density based in the relation 0.5CV2. Due to instability of aqueous electrolyte at high voltages and toxicity of organic electrolytes, potential of hybrid supercapacitor has not been fully exploited.
In this work, we used ionic liquid gel polymer electrolyte having stable potential of ~3.2V to fabricate hybrid supercapacitors with nanofibrous PEDOT and graphene asymmetric electrodes. PEDOT electrode was prepared by ultra-short pulsed current electro-polymerization using LiClO4 in acetonitrile over flexible graphite sheets. Highly mesoporous graphene electrode of 600 m2g-1 surface area was formed by slurry coating using graphene platelets of thickness 8 nm and size <2 μm. Ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) mixed with P(VdF-co-HFP) forms gel electrolyte. Sandwiched between PEDOT and graphene electrodes, it serves as both charge transfer medium and separator in a highly compact and simplified supercapacitor assembly. Electrochemical cyclic voltammetry (CV) plots over 0-2.5V are rectangular about zero current axis and by remaining undistorted at high scan 100 mV.s-1 rates asserts to highly capacitive behavior and fast redox processes comparable to that of graphene double layer electrode. High areal capacitance of 198.3 mF cm-2 (110.2 Fg-1) which scales with potential was realized. CV studies with varied PEDOT thickness led to balancing of stored charge between PEDOT and graphene and in optimized capacitance of hybrid devices. Energy and power density evaluated by systematic charge-discharge plots at different 0.1-0.5 mA.cm-2 current densities show cyclic stability and specific energy 3.7 Wh kg-1 and power 2.53 KW kg-1. With flat stackable solid-state platform, such hybrid supercapacitors were integrated at backside of solar cell module and investigation of charging of supercapacitors by solar cells provided new perspective on direct storage of solar electricity. This paper describes electrode synthesis, design and electrochemical properties of hybrid supercapacitors and energy storage performance in backing up solar cell generated electricity under various power and light levels.
9:00 PM - EE5.9.09
Reduced Graphene Oxide Hydrogel Deposited in Nickel Foam for Supercapacitor Applications: Toward High Volumetric Capacitance
Viet Hung Pham 1,James Dickerson 1
1 Brookhaven National Laboratory Upton United States,Show Abstract
Supercapacitors, a class of electrochemical energy storage devices with superior power densities and long cycling lifetimes, have attracted great attention for the last decade due to their widespread application in backup power supply systems, portable devices, power tools, and hybrid electric vehicles. Graphene is considered as an ideal supercapacitor electrode material due to its large surface area, superior electrical conductivity, good chemical stability, and high mechanical strength. The theoretical specific capacitance of graphene is as high as ~ 550 F/g. The assembly of graphene sheets into three-dimensional interconnected porous microstructures, namely graphene hydrogels, has been considered the most effective approach to utilize these materials in supercapacitors that can achieve high specific capacitances. However, graphene hydrogels typically consist of large amount of water, up to 99 wt. %, resulting in very low graphene packing density. Therefore, the usual volumetric capacitance of graphene hydrogels is very poor, limiting their practical application.
In this study, we report a scalable method to prepare graphene hydrogels with high packing densities through the electrophoretic deposition of graphene oxide onto nickel foam, followed by an electrochemical reduction. The obtained, electrochemically reduced graphene oxide hydrogels (ERGO) on nickel foam were hydraulic compressed (up to 156 MPa) to increase the packing density of ERGO from 0.0098 to 1.32 g/cm3. In a two-electrode symmetric supercapacitor test using 6M KOH electrolyte, the compressed ERGO showed excellent performance with a volumetric specific capacitance up to 176.5 F/cm3 at a current density of 1 A g−1. Further, ERGO exhibited favorable cycling stability with retentions in range of 79 - 90 % after 10,000 cycles, depending on packing density of ERGO.
9:00 PM - EE5.9.10
Cellulose Nanofibril (CNF)–Reduced Graphene Oxide (RGO)–Carbon Nanotube (CNT) Hybrid Aerogels for Highly Flexible and All-Solid-State Supercapacitors
Qifeng Zheng 1,Zhiyong Cai 2,Zhenqiang Ma 3,Shaoqin Gong 4
1 Materials Science Program Univ of Wisconsin-Madison Madison United States,2 Forest Product Lab U.S. Department of Agriculture Madison United States3 Eelectrical and Computer Engineering University of Wisconsin-Madison Madison United States1 Materials Science Program Univ of Wisconsin-Madison Madison United States,4 Biomedical Engineering University of Wisconsin-Madison Madison United StatesShow Abstract
There is an ever-increasing demand for high-performance energy storage systems due to the rapidly growing market in wearable and portable electronics such as roll-up displays and electric paper. Lightweight, high power and energy density, high flexibility, and low cost, as well as environmental friendliness, are someprincipal requirements of these energy storage devices.A novel type of highly flexible and all-solid-state supercapacitor using cellulose nanofibril (CNF)–reduced graphene oxide (RGO)–carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4–poly(vinyl alcohol) gel as the electrolytewas developed andis reported here. These solid-state flexible supercapacitors were fabricated without any binders, current collectors, or electroactive additives. Due to the porous structure of the CNF/RGO/CNT aerogel electrodes, and the excellent electrolyte absorption properties of the CNFs present in the aerogel electrodes, the resulting flexible supercapacitors exhibited a specific capacitance of 252 F g-1 at a discharge current density of 0.5 A g-1, and remarkable cycle stability with more than 99.5% capacitance retained after 1000 charge–discharge cycles at a current density of 1 A g-1. Furthermore, the supercapacitors also showed extremely high areal capacitance, areal power density, and energy density, which were 216 mF cm-2, 9.5 mW cm-2, and 28.4 μWh cm-2, respectively.The study reported here provides a simple and environmentally friendly method for fabricating porous electrode materials based on an abundant and sustainable natural polymer (i.e., CNF) and carbon materials, which possess desirable electrical and mechanical properties for flexible all-solid-state supercapacitors for energy storage.
9:00 PM - EE5.9.11
Freestanding 3D Macroporous Graphene and Polyaniline Nanowire Arrays Hybrid Frameworks for High-Performance Supercapacitors
Pingping Yu 1
1 Fudan Univ Shanghai China,Show Abstract
Flexible, lightweight and wearable supercapacitors have attracted great interests in energy storage because of their potential applications in portable electronic devices, flexible displays, electronic paper and mobile phone.[1-3] The development of supercapacitors has focused on the use of graphene, due to its excellent electric and mechanical properties, chemical stability, high specific surface area up to 2675 m2 g -1, and feasibility for large-scale production.[4-5] Graphene-based nanocomposites have been achieved by incorporating guest nanoparticles onto 2D graphene sheets. However, most of these structures suffer from graphene aggregation, which causes inferior ionic accessibility and thus obtains low electrochemical performance. Therefore, macroscopic graphene framework with three-dimensional interpenetrating structures can solve the issue of poor ionic and electronic transport. In our paper, freestanding three-dimensional hierarchical porous reduced graphene oxide foam (RGO-F) was first fabricated by “dipping and dry” method using nickel foam as the template. Three-dimensional (3D) RGO-F with high conductivity provides a large porosity than that of conventional graphene films. Polyaniline (PANI) nanowire arrays aligned on the foam (RGO-F/PANI) were synthesized by in situ polymerization. A symmetric supercapacitor with high energy and power densities was fabricated using RGO-F/PANI electrode. The highly flexible and mechanically foam can directly serve as an electrode with no binders and conductive additives. Owing to its well-ordered porous structure and high electrochemical performance of RGO-F/PANI composite, the symmetric device exhibits high specific capacitance (790 F g -1) and volumetric capacitance (205.4 F cm -3), showing maximum energy density and power density of 17.6 Wh kg -1 and 98 kW kg -1. Moreover, the device possesses excellent cycle life with 80% capacitance retention after 5000 cycles. Therefore, the 3D lightweight and freestanding symmetric supercapacitor is a promising candidate in the application of high-performance energy storage systems.
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 G. Wang, X. Sun, F. Lu, H. Sun, M. Yu, W. Jiang, C. Liu, J. Lian, Small 8 (2012) 452.
9:00 PM - EE5.9.12
Fabricating Covalent Hybrids of Nanoscaled Cobalt and Cobalt Oxide Polymorphs on Graphene: Towards High-Performance Electrochemical Energy Storage Supercapacitors and Enzymeless Glucose Detection
Sanju Gupta 1,Sara Carrizosa 1
1 Western Kentucky University Bowling Green United States,Show Abstract
In this work, effective strategies for the fabrication of cobalt oxide/graphene hybrid nanostructures are highlighted by focusing on the effects of their structure and morphology producing tailored interfaces on their electrochemical performance. Nanostructure engineering has been demonstrated as an effective approach to improve the electrochemical performance of electrochemical electrode materials. Employing a simple hydrothermal procedure and electrodeposition techniques followed by thermal treatment, cobalt nanoparticles (CoNP) and cobalt oxide polymorphs such as CoO and Co3O4 nanostructures were in-situ synthesized on two- and three-dimensional graphene nanosheets. The structure and morphology of the resulting various covalent graphene/cobalt hybrid composites were characterized by scanning and transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The graphene/ cobalt hybrid composites were investigated as electrochemical electrodes for asymmetric supercapacitor application and as electroanalytical platforms for enzymeless detection of glucose. We demonstrated that Co3O4/ErGO and Co3O4/multilayer graphene hybrids are capable of delivering high specific capacitance of > 600 F g-1 at a current density of 10 A g-1 is achieved when the mass ratio of Co3O4 to ErGO is equal to 80:20 as compared with other hybrids with excellent cycling stability in a voltage of 0–1.2 V. It can also detect glucose with a ultrahigh sensitivity of 3.57 mA mM-1 cm-2 and a remarkable lower detection limit of < 50 nM. We gratefully acknowledge the financial support in parts by NSF KY EPSCoR and WKU Research Foundation.
9:00 PM - EE5.9.13
Recycling Waste Si Wafer for Supercapacitor Electrodes by Conversion to Micro/Mesoporous SiC Flakes
Myeongjin Kim 1,Kiho Kim 1,Hyun Ju 1,Jooheon Kim 1
1 Chung-Ang Univ Seoul Korea (the Republic of),Show Abstract
Micro- and meso-porous SiC flakes with a high surface area of about 1376 m2g-1 were obtained by one-step carbonization of waste Si wafer without any chemical or physical activation. The micro-pores are formed by the partial evaporation of Si atoms during the carbonization process and meso-pores are derived from the combination of neighboring micro-pores. These dual pore systems can supply enhanced electric double layer capacitance by micro-pores and reduced resistant path with excellent charge propagation by meso-pores. Two-electrode supercapacitor cells constructed with this SiC yielded high electrochemical performance with aqueous and organic electrolytes. The outstanding electrochemical performance opens up new possible applications as supercapacitor electrodes based on this form of SiC.
9:00 PM - EE5.9.14
High Performance Energy Storage Material from Bio-Waste
Charith Ranaweera 1,Pawan Kahol 1,Petar Dvornic 1,Ram Gupta 1
1 Pittsburg State Univ Pittsburg United States,Show Abstract
To meet increasing demands for energy from sources other than fossil fuels, it is a perfect time to develop sustainable and reproducible energy storage devices. Recent efforts have focused on more efficient energy storage devices including supercapacitors which have high power densities, fast charge–discharge capabilities and long life cycles. Such supercapacitors are aimed at emergency power systems, electric vehicles, and devices where high-power delivery is required, and several types of materials, such as metal oxides and conducting polymers have been used for their electrodes. However, most of these materials often suffer from low capacitance and high cost, so in this work, we attempted to use orange peel, a bio-waste, for electrochemical charge storage applications. The electrochemical properties of the car