Steve Harris, Lawrence Berkeley National Laboratory
Ping Liu, Advanced Research Projects Agency-Energy (ARPA-E)
Jie Xiao, Pacific Northwest National Laboratory
Yan Yao, University of Houston
LL2: Solid State Electrolyte
Monday PM, November 30, 2015
Hynes, Level 3, Room 309
2:30 AM - *LL2.01
All-Solid-State Li-Ion Batteries for Transformational Energy Storage
Eric David Wachsman 1 Gregory Hitz 1 Dennis Wayne McOwen 1 Yang Wen 1 Yunhui Gong 1 Xiaogang Han 1 Kun Fu 1 Huili Liu 1 Liangbing Hu 1 Chunsheng Wang 1 Venkataraman Thangadurai 2
1University of Maryland College Park United States2University of Calgary Calgary CanadaShow Abstract
We have developed transformational, and intrinsically safe, all-solid-state Li-ion batteries (SSLiBs), by incorporating high conductivity garnet-type solid Li-ion electrolytes into tailored tri-layer microstructures, by low-cost solid oxide fuel cell (SOFC) fabrication techniques to form electrode supported dense thin-film (~10mu;m) solid-state electrolytes. The microstrucurally tailored porous garnet scaffold support increases electrode/electrolyte interfacial area, overcoming the high impedance typical of planar geometry SSLiBs resulting in an area specific resistance (ASR) of only ~2 Omega;cm-2 at room temperature. The unique garnet scaffold/electrolyte/scaffold structure further allows for charge/discharge of the Li-metal anode and cathode scaffolds by pore-filling, thus providing high depth of discharge ability without mechanical cycling fatigue seen with typical electrodes. Moreover, these scalable multilayer ceramic fabrication techniques, without need for dry rooms or vacuum equipment, provide for dramatically reduced manufacturing cost.
Fabrication of supported dense thin-film garnet electrolytes, their ability to cycle Li-metal at high current densities with no dendrite formation, and results for Li-metal anode/garnet-electrolyte based batteries with a number of different cathode chemistries will be presented.
3:00 AM - *LL2.02
All-Solid-State and Aqueous Li-Ion Batteries
Chunsheng Wang 1 Kang Xu 2 Fudong Han 1 Liumin Suo 1
1Univ of Maryland College Park United States2Army Research Lab Adelphi United StatesShow Abstract
Safe Li-ion battery is critical for success of electric vehicle, and the electrolytes are one of the most important component for the safety of the Li-ion batteries. In this talk, we summarize the research progress of our group on all-solid-state Li-ion batteries and aqueous Li-ion batteries. In all-solid-state Li-ion battery, we report a novel concept of a single-material all-solid-state lithium-ion battery, wherein a single Li10GeP2S12 serves as an electrolyte, an anode, and a cathode, to eliminate the highly resistive interface between the electrodes and electrolyte. The realization of the single-Li10GeP2S12 battery is based on the fact that the Li-S and Ge-S components in Li10GeP2S12 could act as the active centers for lithiation/delithiation as a cathode and an anode, respectively, when electronically-conductive carbon is mixed, while pure Li10GeP2S12 can be used as an electrolyte. This unique concept of a single-material lithium-ion battery can be extended to other solid-state battery systems, providing a new direction for high-power, high-energy, long-cycling solid-state batteries. For aqueous Li-ion battery, we report a new aqueous electrolyte, whose electrochemical stability window was expanded to ~3.0 V. A full Li-ion battery of 2.0 V was demonstrated to cycle over 1000 times in this electrolyte, with nearly 100% Coulombic efficiency at both low (0.15 C) and high (4.5 C) rates.
4:00 AM - LL2.03
3D Printing Solid-State Li-Ion Batteries
Dennis Wayne McOwen 1 Gregory Hitz 1 Tanner Hamann 1 Eric David Wachsman 1
1University of Maryland Energy Research Center College Park United StatesShow Abstract
Over the last decade, Li-ion batteries have begun to dominate several energy storage markets due to the many inherent advantages of Li-ion chemistry. More recently, a new approach to Li-ion battery technology has been investigated—utilizing solid-state electrolytes made of lithium garnet-type ceramics. (e.g. Li7La3Zr2O12 or LLZ) These materials are inherently non-flammable and contain no toxic or reactive fluorine. Importantly, garnet materials like LLZ are electrochemically stable to Li metal (enabling higher energy density batteries), and are also thermally stable and mechanically strong. The main areas challenging the development of all-solid-state Li-ion batteries, however, have been low ionic conductivity and high interfacial impedance due, in part, to poor solid-solid contact. The ionic conductivity of garnet materials has been steadily increasing as new compositions/dopants are discovered and sintering conditions are optimized. However, if a method existed which could provide precise control over the microstructure, both of the issues could be resolved. First, the thickness of the electrolyte separating the two electrodes could be reduced to the order of tens of microns, such that the overall resistance of the bulk electrolyte would become negligible. Secondly, by tailoring the architecture of the contact surface of the electrolyte with the electrode, the interfacial impedance could be similarly reduced.
With the recent growth and maturation of 3D printing, such precise control over microstructure is now possible, both for scientific and technical applications. Using a 3D printer armed with devices such as a UV lamp for photopolymer spot curing and a laser for laser sintering, not only can the microstructure of the solid electrolyte be adequately controlled, but the interface with the anode and cathode can be modified as well. This presents a distinctive way of quickly fabricating unique, ordered architectures to address the impedance issues described above. Using a 3D printer, thin solid-state batteries have been printed using different microstructures/architectures for each component to explore the effect of each on battery properties. For example, the aspect ratio has been found to significantly impact the performance metrics. Additionally, using characterization tools such as electrochemical impedance spectroscopy, Raman spectroscopy, and SEM, bulk properties and interfacial effects can be investigated with a high degree of accuracy. In this way, both macro and microscopic spatial variations of structure and composition will be probed.
4:15 AM - LL2.04
Investigation of a Polymer Electrolyte/Cathode Interface in a Solid-State Lithium Battery
Matthew D. Widstrom 2 Arthur Von Wald Cresce 1 Peter Kofinas 3 2
1US Army Research Lab Adelphi United States2University of Maryland College Park College Park United States3University of Maryland College Park College Park United StatesShow Abstract
Solid polymer electrolytes (SPEs) possess an inherent safety advantage over traditional liquid carbonate electrolytes, and can be incorporated into an effective solid-state battery at physiological temperature for use in implantable devices. In this work, we report on our progress towards the goal of the development of a solid-state battery utilizing a SPE. The electrochemical properties of a SPE using a poly(ethylene oxide) (PEO) polymer matrix in the presence of tri-ethyl sulfonium bis(trifluorosulfonyl) imide (S2TFSI) ionic liquid (IL) and lithium TFSI with appreciable ionic conductivity ~ 1 mS/cm at physiological temperature are presented. These homogenous, mechanically robust films were fabricated via a hot-pressing method and incorporated into lithium metal/SPE/lithium cobalt oxide or lithium iron phosphate pouch cells where the cycling performance and rate capability were assessed. The cells were disassembled post-mortem and the SPE/cathode interface was examined using a dual FIB-SEM system whereby FIB was used to expose fresh SPE/cathode interface and SEM was used for imaging and elemental composition analysis.
4:30 AM - *LL2.05
Biomimetic Solid Electrolyte
Yunfeng Lu 1
1UCLA Los Angeles United StatesShow Abstract
Lithium-ion batteries (LIBs) are one of the most widely used energy storage devices in modern society, and they are playing important roles in the rapidly developing markets of pure/hybrid electric vehicles and other large-scale energy storage systems. Current LIBs utilize flammable liquid electrolytes, which have brought potential risks, especially for large-scale applications. Moreover, additional problems emerge when moving to advanced systems beyond conventional LIBs, such as lithium-sulfur and lithium-air batteries, where the use of metallic lithium as anode would cause dendrite formation and raise safety concerns regarding short circuit. Solid electrolytes have been considered as feasible solutions to the safety issues of liquid ones.
Continuous efforts have been devoted in the past few decades to search new materials for solid electrolytes, which mainly include ceramic-based and polymer-based electrolytes. In this work, a novel class of solid electrolytes with biomimetic ionic channels will be discussed, providing a new direction towards high-performance and robust LIBs.
5:00 AM - LL2.06
Innovative Alumina Nanofluid-Based Electrolyte for Thermo-Electrochemical Cells
Chang Liu 1 Shien Ping Feng 1
1The University of Hong Kong Hong Kong ChinaShow Abstract
Thermo-electrochemical cells with aqueous electrolyte that convert low-grade heat (<130 degree Centigrade) directly into electrical energy, has attracted considerable attentions as an alternative strategy to thermal energy harvesting. However, innately poor electrical conductivity of aqueous ferro/ferricyanide electrolyte is one of critical factors to limit the efficiency of thermal-electrochemical cells. In order to enhance electrical conductivity and diffusivity of the electrolyte, applying nanoparticles into the electrolyte which is called electrolyte-based nanofluids can be one of promising ways for the augmentation of mass transport in the electrolyte through the combined effect of percolation behavior and convection. The presence of nanoparticles in electrolyte is seldom studied due to intrinsic instability of nanofluids, especially, in electrolyte with high ionic strength. Moreover, the collocation of base fluids and nanoparticles are strictly restricted by both chemical and physical properties for a stable nanoparticles suspension. Here we report a practicable approach fabricating γ-alumina nanofluid-based ferro/ferricyanide electrolyte equipped with enhanced electrical conductivity and feasible stability by introducing stirred nano-bead milling in conjunction with ultrasonication. Sodium dodecyl sulfate is introduced to stabilize alumina nanoparticles in ferro/ferricyanide electrolyte by constructing steric barriers. 0.2M alumina nanofluid-based ferro/ferricyanide electrolyte holds an ionic concentration 20-fold higher than previous work in the literature, providing practical significance to develop nanofluid-based electrolyte for thermo-electrochemical cells. Based on electrical conductivity and rotating disk electrode studies, the diffusivity of alumina nanofluid-based electrolyte at a nanoparticle mass fraction of 0.25% shows a mutative response to convection, revealing a critical deviation from homogeneous standard ferro/ferricyanide electrolyte at high angular velocities. We decipher this conspicuous increase of the limiting current as a result of both percolation behavior and convection under shear flow. Additionally, alumina nanofluid-based electrolyte is confined by relatively high viscosity, which counteracts to the thermal conductivity. 0.2M alumina nanofluid-based ferro/ferricyanide is demonstrated in thermo-electrochemical cells to capture a progressive figure of merit of 29.9×10-6K-1.
5:15 AM - LL2.07
Surface Oxygen Exchange Kinetics for Solid-Oxide-Electrolyte Metal-Air Batteries
Gil Cohn 1 Jie Wang 2 Kevin Huang 2 Eric D. Wachsman 1
1University of Maryland College Park United States2University of South Carolina Columbia United StatesShow Abstract
A new type of all-solid-state metal-air battery is being developed by the University of South Carolina, based on a reversible solid oxide fuel cell. The operation of this metal-air battery is based on Oshy;2- conduction, and is able to provide high specific energy and high round-trip efficiency at a temperature as low as 550oC. However, operation at temperature lower than 550oC requires a new class of high conductivity catalytic oxide-ion electrolyte. For that propose, a new cobalt-based perovskite oxide with high catalytic activity for oxygen reduction was developed.
Here we report on the surface exchange properties of that new material, SrCo0.9-xNb0.1FexO3-δ, by means of in-situ oxygen isotope exchange. We used our unique heterogeneous catalysis system to determine the oxygen exchange rate coefficients and mechanism for a variety of Fe doping concentrations. Oxygen exchange profiles indicate an enhanced exchange properties of SrCo0.9Nb0.1O3-δ over the other Fe concentrations. Exchange of 18O2 reaches a saturation at 450-500oC, while below 300oC the exchange is very slow. Fitting the exchange results to a model describing the exchange process we were able to extract the temperature dependence of the exchange coefficient as well as the activation energy for oxygen exchange and compared with the literature data. Reaction order, together with the identity of the oxygen species taking part in the reaction are also investigated through variation in the oxygen partial pressure. The results explicity show an extensive oxygen exchange abiltiy of the electrolyte at intermidiate temperatures.
LL3: Poster Session I
Monday PM, November 30, 2015
Hynes, Level 1, Hall B
9:00 AM - LL3.01
Development of a Flexible High Potential Thin Film Zinc-Air Battery by Screen Printing Technique
Sira Suren 1 Soorathep Kheawhom 1
1Chulalongkorn Univ Bangkok ThailandShow Abstract
This work investigates the development of a flexible high potential thin film zinc-air battery by screen printing technique. Commercial Ag ink was used as the anode and cathode current collectors. Polypropylene membrane was used as the separator. 9 M KOH was used as the electrolyte. Mixture of Zn powder, ZnO, and Bi2O3 was used as the anode electrode. Types of cathode active materials (carbon paper and carbon black) were investigated. Results showed that batteries using carbon paper and carbon black as active materials provided the open-circuit voltage at 1.44 and 1.45 V, respectively. When batteries were discharged at 0.15 mA/cm2, the open-circuit voltage observed from both batteries using carbon paper and carbon black as the active materials were 1.23 V. Battery using carbon black showed a little longer discharging time. Energy density observed from battery using carbon black was 682 Wh kg-1 and that using carbon paper was 323 Wh kg-1.
9:00 AM - LL3.02
Transparent Thin Film Cathode Electrode for Zn-MnO2 Battery Fabrication
Sira Suren 1 Thanatham Julaphatachote 1 Soorathep Kheawhom 1
1Chulalongkorn Univ Bangkok ThailandShow Abstract
Transparent cathode electrode has been successfully fabricated with microelectrode array pattern using screen printing technique. The result from UV/Vis spectra between 400 to 800 nm indicated that battery with an electrode area of 25 percent (battery A) had transparency of 82 percent, while battery with an electrode area of 20 percent (battery B) had transparency of 86 percent. It can be concluded that transparency of the electrode is inversely proportional to the electrode area percentage. Potentiostat was used to determine the prototype batteries performances. Both battery A and battery B provided the same open-circuit voltage at 1.3 V indicating that the electrode area percentage had no effect on the open-circuit voltage. Both batteries had similar shape of current-voltage characteristic, however, battery A had a flatter slope in the Ohmic polarization region compare with battery B, indicating that battery A could provide more stable current at a given voltage. This was due to higher contact area between the microelectrode array and the electrolyte of the battery A than that of battery B. Nevertheless, further optimization of the battery is still needed in order to make it applicable to be functioned as a transparent energy source for transparent device.
9:00 AM - LL3.03
Single Walled Carbon Nanotube - Cobalt Oxide Nanocomposites as Supercapacitor Electrode Materials
Mete Batuhan Durukan 1 Recep Yuksel 2 Husnu Emrah Unalan 1
1Middle East Technical University Ankara Turkey2Middle East Technical University Ankara TurkeyShow Abstract
While the double-layered supercapacitors that use carbon materials with high surface areas are commercialized; metal oxide active materials has attracted much more attention in recent years. This is because of their pseudocapacitive behavior; high redox activity and high reversibility. Cobalt oxides (Co3O4 and CoOx) are reported to have high pseudocapacitive properties, which make them promising electrode materials for supercapacitors. Hybrid capacitors using multi-walled carbon nanotubes and cobalt oxides are reported to have high capacitance values; however, research on electrodeposition of cobalt oxide onto single walled carbon nanotube thin films and supercapacitors fabricated by this means with a low-cost route remained elusive.
In this work, single walled carbon nanotube (SWNT) and cobalt oxide hybrid electrodes were prepared and tested. SWNT thin films were fabricated via a low-cost vacuum filtration and consecutive stamping method onto glass substrates and cobalt oxides were electrodeposited from a cobalt nitrate solution. Co3O4 phase is obtained by annealing the as- electrodeposited specimen. The capacitive behavior of the hybrid supercapacitors was investigated through cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The total charge transfer and Faraday&’s Law were used to obtain the amount of electrodeposited cobalt oxide. A specific capacitance of 230 F/g was obtained at a scan rate of 1 mV/s for the hybrid electrodes. A detailed analysis on the capacitive behavior will be presented in conjunction with the oxidation states and morphology of the active materials.
9:00 AM - LL3.04
Single Walled Carbon Nanotube - Conducting Polymer Electrodes for Electrochromic Supercapacitors
Recep Yuksel 2 Ali Cirpan 3 Husnu Emrah Unalan 1
1Middle East Technical University Ankara Turkey2Middle East Technical University Ankara Turkey3Middle East Technical University Ankara TurkeyShow Abstract
Supercapacitor devices are complementing batteries with their high power and moderate energy densities. There are commercial batteries that show the remaining battery power through a gauge by means of a thermochromic indicator that measures the heat resistance. Likewise, what if the supercapacitors are made to reveal their stored capacity? One could use electrochromic polymeric materials for this purpose to reflect the stored capacity via color change. A new benzotriazole (BTz) and dithienothiophene (DTT) containing conducting polymer (CP) is emerged as a promising active material both for its electrochromic and electrochemical properties combined in a single device. In this work, we report on the fabrication and characterization of supercapacitors with single walled carbon nanotube (SWNT) and new CP network electrodes. Vacuum filtered SWNT thin films in this work provided high surface area, high conductivity and high transparency for the electrochromic polymer. CP was deposited onto SWNT thin films by drop-casting and experienced multiple color changes with respect to its charged state. Specific capacitance of SWNT/CP nanocomposite electrodes was obtained to be 112 F/g, which was higher than that of bare SWNT electrodes. We will present a detailed analysis of the electrochromic and electrochemical properties of the fabricated supercapacitor electrodes.
9:00 AM - LL3.05
The Bulwark of Multiple Surface Modifications to Revive the Recycled Waste for Si-Based Lithium Ion Battery
Bing-Hong Chen 1 Shang-I Chuang 1 Jenq-Gong Duh 1 Hao Yang 1
1National Tsing Hua University Hsinchu TaiwanShow Abstract
Unlike the conventional manufacturing to synthesize nano-silicon with special morphology for lithium ion battery, the peculiar anode material was extracted from the wastes of solar cell industries, which is oversize in micro scale with irregular morphology. Instead of most efforts to avoid the volume expansion, this study demonstrates a multiple surface modifications of atmospheric pressure plasma and carbon overlayer to build a bulwark between electrode and electrode. With different combination of surface modification, the surface chemical bonds of electrode and carbon overlayer were rearranged and nitrogen were revealed to be doped onto the electrode material through the examination of XPS. Raman spectroscope was adopted to verify the ratio of order and disorder of carbon overlayer with/without plasma treatment. The distinct bulwark was formed on the surface which have the function to mitigate the sever formation of solid electrolyte interface (SEI). The enhanced performance was examined between voltage window of 0.05 and 1.2 V with stable retention and high Coulombic efficiency. Through the analysis of cyclic voltammetry and AC impedance, the electrochemical properties were evaluated with the insertion/extraction behavior and internal circuit resistances. Furthermore, the etching profile of XPS interpreted the difference in multiple surface modifications, and provided the evidence of the bulwark after first cycling. Finally, the combination of plasma treatment and carbon layer gives the waste with a new life for potential application.
9:00 AM - LL3.06
Synthetic Control of Composition and Crystallite Size of Silver Ferrite Composites: Profound Electrochemical Impacts
Jessica Durham 1 Kevin Kirshenbaum 2 Amy Marschilok 1 Esther Sans Takeuchi 1 2 Kenneth Takeuchi 1
1Stony Brook Univ Stony Brook United States2Brookhaven National Laboratory Upton United StatesShow Abstract
Silver ferrite, AgFeO2, exhibits a layered delafossite-type structure with the general chemical formula ABO2. A low-temperature, aqueous co-precipitation reaction employing non-stoichiometric ratios of starting materials, AgNO3 and Fe(NO3)3, was developed allowing for the manipulation of composition (AgxFeO2, 0.2 le; x le; 1.0) and crystallite size (10-18 nm). The composite nature of the low silver materials as a combination of crystalline silver ferrite, AgFeO2, and non-crystalline maghemite, γ-Fe2O3, was established by Raman spectroscopic and X-ray absorption analyses. The layered structure of delafossites enables ion transport and a limited number of literature reports describe exploration of silver delafossite oxides as cathodes in lithium-based batteries, including an investigation of AgCuO2 and AgCu0.5Mn0.5O2. Studies of AgFeO2 demonstrated that stoichiometric silver ferrite, with an Ag : Fe ratio of 1 : 1 and an average crystallite size of 31 nm, is electrochemically active. As a cathode, the low silver content composites (x = 0.2) exhibited significantly enhanced electrochemical performance with capacities approximately100% higher relative to stoichiometric AgFeO2 and demonstrated the lowest capacity fade. The synthetic approach demonstrated herein provides a new paradigm for composite synthesis, offers an economically feasible method to prepare electrode materials, and is applicable for industrial scales. This research can be applied to viable electrode materials to increase the efficacy and energy density of modern battery technologies.
9:00 AM - LL3.07
Progress towards High-Power Li/CFx Batteries: Electrode Architectures Using Carbon Nanotubes with CFx
Qing Zhang 1 Kenneth Takeuchi 1 Esther Sans Takeuchi 1 2 Amy Marschilok 1
1Stony Brook Univ Stony Brook United States2Brookhaven National Laboratory Upton United StatesShow Abstract
The lithium-carbon monofluoride (Li/CFx) battery system exhibits desirable battery characteristics of high energy density (exceeding 2000 Wh/kg), long shelf-life, and low self-discharge. These batteries have been utilized in a wide range of applications including implantable medical devices, portable communication devices, and military and aerospace electronics. However, the broader application of Li/CFx batteries has been limited by their power capability. Multi-walled carbon nanotubes (CNT) are appealing additives for high-power batteries, due to their outstanding electronic conductivity, long aspect ratio necessitating low volume fraction for percolation and high flexibility. This summary describes the current state-of-the-art in Li/CFx batteries and highlights opportunities for development of high-power LI/CFx batteries via utilization of CNT. In our research, we investigated the resistivity of CFx combined with CNT and compared the CFx-CNT composites with conventional carbon additives. We investigated CFx-CNT electrodes without metallic current collectors and compared their electrochemical performance with conventional CFx electrodes using metallic current collectors. Furthermore, we fabricated multilayered CNT-CFx-CNT electrodes (sandwich-structure electrodes) and studied the influence of structure on performance of the electrode. By generating several electrode architectures using CFx-CNT combinations and investigating the impact of CNT on the electrochemical performance, we demonstrated the opportunities for utilization of CNT in CFx electrode and the promising implementation of CFx electrode in next-generation high-power batteries.
9:00 AM - LL3.08
Activated Carbon Derived from Agricultural Waste Streams for Energy Applications
Lucas Servera 1 Paul Raymond Armstrong 2 Kofi Wi Adu 2 3 Angela Lueking 1 3
1Pennsylvania State University Altoona United States2Penn State - Altoona College Altoona United States3Pennsylvania State University University Park United StatesShow Abstract
The unique structural architecture of carbon-based nanoporous structures such as activated carbon (AC) has made activated carbon one of the most viable materials to address current environmental challenges. The highly developed porosity, large surface area, tunable surface chemistry, and high degree of surface reactivity make AC the most widely used adsorbent for the removal of wide variety of organic and inorganic pollutants dissolved in aqueous media or from gaseous environments, as well as the use as electrodes in energy related applications. Traditional feedstocks for AC production include, primarily, mineral carbons, and lignocellulosics from biomass and wood. However, any cheap material, with a high carbon content and low mineral content, can be used as a precursor for the production of AC. Agricultural wastes are proving to be promising precursors for the production of ACs mainly due to their availability, low cost and zero carbon foot print. We present preliminary investigation on utilized mechanical ball milling followed by chemical activation technique to convert agricultural waste (cocoa and coconut husks, palm midribs and calabash) into ultra-high surface area activated carbon suitable for myriads of environmental and energy related applications. Our preliminary investigation indicates about 70% increase in BET surface area with ball milling to as high as ~ 3000 m2/g, and shows potential application as electrode material in supercapacitors.
9:00 AM - LL3.10
Influence of Graphene-Chitosan Nanoplateles in the Direct Electron Transfer Process of Enzymes
Tiago Pedroso Almeida 1 2 Frank Hollmann 2 Celina Massumi Miyazaki 3 Antonio Riul 1
1Unicamp Campinas Brazil2TU Delft Delft Netherlands3UFSCar Sorocaba BrazilShow Abstract
Multilayer films of Graphene-Chitosan nanoplatelets with glucose oxidase were assembled using the layer-by-layer (LbL) technique. The aim here is a better comprehension of how the presence of Graphene-Chitosan (G-Chitosan) nanosheets present in the LbL nanostructured multilayers influences the direct electron transfer process between enzyme and electrode. The LbL assembly was chosen due to its simplicity and versatility to produce thin films with controllable thickness and morphology, taking the advantage of nanoscale engineering to create tailored architectures that can hold the enzyme inside the multilayers formed, with fine control in the film composition and structure. The G-Chitosan choice was based on the possible biological compatibility and possibility to support a direct electron transfer (DET) mechanism between active center inside the enzyme and the electrode. Here, UV-vis was used to investigate the film formation and also the structure of the enzyme immobilized, which was also characterized by potentiometric measurements to check the DET process. Our results indicated good adherence and linear growth of the (G-Chitosan/Gox) LbL films, and also a DET dependence on the film structure. In summary, we believe that the LbL multilayer assembly facilitates the DET as some nanoplatelets are becoming closer to the active center of the enzymes.
9:00 AM - LL3.11
Tungsten Selenide as a High Capacity Anode for Sodium Ion Batteries
Keith Share 1 John Lewis 2 1 Landon Oakes 2 Adam Paul Cohn 2 Cary Pint 2
1Vanderbilt Univ Nashville United States2Trinity University San Antonio United StatesShow Abstract
WSe2shy; is used for the first time as a sodium ion battery anode and shows a high capacity of 253 mAh/g at a rate of 10 mA/g during the first sodium extraction. This is comparable to or higher than other commercially available transition metal dichalcogenides (TMDs). WSe2 is compared to WS2 and demonstrates a higher specific performance, better rate capability, and less capacity fade. WSe2 also shows a small overpotential of 0.25 V between the anodic and cathodic peaks which is promising for practical applications. Ex situ Raman spectroscopy, X-r