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Home , Solid oxide fuel cell

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Advanced SOFCs and Li- Batteries Successful development OFC technology dominates competing Effect of Surface Condition on the and deployment of cell technologies because it uses Interfacial Strength of Scale and cost-effective clean Scurrently available fossil , reducing SS441 Substrate Used in SOFC operating costs. Other technologies Wenning Liu, Xin Sun, Elizabeth Stephens, energy systems require (e.g., molten carbonate, , and Mohammad Khaleel in-depth understanding phosphoric acid and alkali) require as Pacific Northwest National Laboratory of the fundamental their fuel. Oxidation reaction of the metallic intercon - electrochemical Lithium-ion batteries are popular because nects in a typical SOFC working environment is they have a number of important advantages unavoidable. Oxide scale can delaminate and processes, synthesis, over competing technologies including being eventual spall during stack cooling, which can identification, and lighter than other types of rechargeable batter - lead to serious cell performance degradation. In - development of novel ies of the same size, they hold their charge (a terfacial adhesion strength between the oxide materials, relevant lithium-ion battery pack loses only about 5% its scale and substrate is crucial to the reliability and thermodynamics and charge per month, compared to a 20% loss per durability of the metallic interconnect in SOFC month for NiMH batteries), have no memory operating environments. We investigated the ef - kinetics, knowledge of effect, and can handle hundreds of charge/ fect of the surface finish on the interfacial materials science discharge cycles. strength of oxide scale and SS441 substrate by ap - principles, identification A great amount of work is being conducted plying an integrated experimental/analytical and development of to improve the performance of oxide fuel methodology to quantify the interfacial adhesion cells (SOFC) and lithium-ion batteries as indi - strength. Contrary to the conventional sense, the cost effective large cated by the number of sessions devoted to rough surface of SS441 substrate decreases the scale manufacturing these areas of research and presentations being interfacial adhesive strength of the oxide scale processes, and rational delivered at MS&T’10 during the week of Octo - and SS441 substrate. Interfacial strength is en - engineering design and ber 17 in Houston. We present here several ab - hanced with decreasing surface roughness up to integration of the stracts as a representative cross section of some a plateau, above which the surface finish will not of the most recent developments in these areas. help to improve the interfacial strength of the systems. oxide scale and SS441 substrate. Diffuse Interface Simulations of Ionic Diffusion in Solid Oxide Fuel Cell and AISI441 Interconnect-Air Rechargeable Battery Interfacial Study for Solid Oxide Hui-Chia Yu, Hsun-Yi Chen, and Fuel/Electrolyzer Cell Katsuyo Thornton, University of Michigan Kathy Lu and Tony Jin, Virginia Tech Current generation and transport in elec - This study combines materials processing, trochemical systems often involve transport testing, and characterization capabilities to un - through multiple phases (electrolyte and elec - derstand solid oxide fuel/electrolyzer cell trodes) and reactions at electrode surfaces hav - (SOF/EC) interconnect-electrode interfacial re - ing complex geometries. Therefore, a action and degradation. A yttria-stabilized zir - simulation of the diffusion process using a real - conia (YSZ) electrolyze/strontium-dropped istic microstructure helps to elucidate the mi - lanthanum manganite (LSM)/AISI 441 intercon - crostructural effects on energy conversion. We nect half cell was fabricated, and the assembly developed a numerical method to simulate bulk was sintered and thermally treated in both air diffusion with surface diffusion and surface re - and moist air atmospheres at 800°C for different action as boundary conditions imposed on the times. Different gas flow rates were applied to complex electrode surfaces. The method uses simulate actual cell operating conditions. Inter - a phase-field like domain parameter to differ - face morphology was characterized by means of entiate the solid phase from its environment; microstructural analysis, and Cr diffusion and thus, no structural meshing technique is re - air electrode degradation behaviors were inves - quired. Two applications, oxygen vacancy dif - tigated at different thermal treatment times. We fusion in solid oxide fuel cell (SOFC) cathodes provide a comprehensive, integrated approach and electrochemical processes in rechargeable to understanding material interfacial behaviors battery cathodes, will be discussed. and a completely new paradigm of directed ma -

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terial design under high temperature theoretical gravimetric and volumetric conditions. SOFCs can be used in military applications, such as specific capacity compared to cur - powering individual soldier’s equipment, as well as in commercial power plants, for rently used carbon . However, Mechanical Properties of a residential and commercial use, and auxiliary power the severe crystallographic volume Barium Silicate Glass Seal for units for public and personal transportation. changes that occur during the lithium Solid Oxide Fuel Cells (SOFCs) Also, SOFC’s may be clustered for large-scale alloying and dealloying processes lead stationary power generation. Courtesy of Pacific Amit Shyam, Rosa Trejo, Yanli Wang, Northwest National Laboratory. to mechanical failure of the Si-based and Edgar Lara-Curzio anodes, eventually resulting in failure ORNL of the entire battery. A composite based on Si homogeneously dis - The mechanical properties of a barium silicate-based glass that persed and distributed within a suitable matrix is expected to im - are relevant for its function and performance as a seal for SOFC prove the structural stability and cyclability of the electrode. systems were characterized between ambient temperature and 850°C. The temperature dependence of viscosity was determined Li2MnO3-LiMO2 (M=Mn, Co, Ni) Solid Solutions with using a thermomechanical analyzer, and results obtained from Surface Coatings to Improve Li-ion both static and dynamic methods are in good agreement. The Performance of the glass, its glass transition temperature, William West, Jess Soler, Marshall Smart, and its elastic modulus also were determined. The wetting behav - and Bugga Ratnakumar ior of the glass on alumina and zirconia substrates was investi - Jet Propulsion Laboratory gated using the sessile drop method. The contact angle decreases The Li 2MnO 3-LiMO 2 (M=Mn, Co, Ni) materials system is with time for both substrates and the results are analyzed using an attractive Li-ion battery cathode given its high specific capac - existing models for dynamic contact angle changes. Models to de - ity of upwards of 240 to 280 mAh/g between 4.8 and 2 V. How - scribe the relationship between wetting behavior and viscous flow ever, these cathode materials are somewhat rate limited with will be discussed. This material is based on work supported by the comparatively low cycle life relative to other cathodes such as Department of Energy National Energy Technology Laboratory LiNi(1-x)CoxO 2. To improve the rate capability and cycle life, we under Award Number FEAA066 conducted a number of materials and electrochemical charac - . terization studies of these cathode materials prepared with var - Impact of Impurities and Alloying Metals on the ious surface coatings. The studies were conducted to optimize Performance of Liquid Metal the cathode material to meet the NASA targeted goal of 280 Solid Oxide Fuel Cells mAh/g between 4.8 and 3V at a C/2 discharge rate at 0 oC. The ef - Harry Abernathy, Richard Pineault, and Kirk Gerdes, fects these coatings have on cell discharge rate, cycle life, spe - National Energy Technology Laboratory cific capacity, and irreversible capacity are presented for two The liquid tin anode solid oxide fuel cell (LTA-SOFC) has at - electrode coin cells and three electrode spiral wound cells. tracted attention recently due to its ability to run directly on pul - verized or other solid, carbon-containing fuels, eliminating Self-Assembled Polymer Derived C/SiCN the need for a gasifier. However, such a convenience comes at Nanocomposites as Promising Anode Materials the expense of decreased power density, requiring more cells to for Li-ion Batteries generate the same amount of power. The possibility of improv - Cheng Li, Yong Chen, and Linan An ing cell performance relies on improving oxygen transport Advanced Materials Processing and Analysis Center through the liquid tin layer, as well as improving the reactivity University of Central Florida of the fuel/anode interface. We discuss the impact of tin purity Self-assembled nanocomposites comprising SiCN matrix level and alloying element selection on the oxygen diffusivity and nanosized C particles were synthesized by thermal decom - through the anode and on the interfacial polarization resistance position of polymeric precursors and the electrochemical prop - based on thermodynamic calculations and electrochemical erties including the charged/discharged lithium capacity and measurements. These liquid tin alloy parameters establish the cycle properties were measured. The materials are promising limitations for the ultimate design of an LTA-SOFC system. anode materials for Li-ion battery applications with a first dis - charge capacity of 853 mAh/g and reversible capacity as high as Si/C Based Composite Anodes for Lithium Ion Batteries 470 mAh/g. Comparison of the electrochemical performance of Prashant Kumta and Moni Datta the materials with that of hard carbon and structural analysis University of Pittsburgh suggest that the uniformly distributed voids resulting from the Rechargeable lithium ion batteries consisting of crystalline or bonding mismatches between the carbon and SiCN are likely the amorphous silicon anodes have gained interest due to their high main lithium storage sites.

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