LSGM Based Composite Cathodes for Anode Supported, Intermediate Temperature (600-800 degrees C) Solid Oxide Fuel Cells (SOFC)

70437S02-II Increasing the power density of solid oxide fuel cells (SOFC) can substantially reduce the costs of SOFC technology by decreasing the stack size, which in turn decreases the amount of materials necessary, reduces the size of the balance of plant, and decreases the size and amount of requisite stack hardware and insulation. Likewise, lowering the operating temperature of SOFC lowers costs due to higher operating efficiency and the use of inexpensive metallic materials, less thermal insulation, and simplified heat management. This project will develop an anode-supported, thin-film YSZ electrolyte SOFC with composite cathodes comprised of the ionic conductor Lanthanum-Gallate (LSGM) and an electrocatalyst. Because LSGM exhibits high oxide ion conductivity (higher than YSZ), it can substantially lower the overpotential at the cathode and thus increase the power density of the SOFC. In addition, the thin-film YSZ electrolyte (~5 microns) and the LSGM-based composite cathode would enable the SOFC to operate at lower temperatures (600-650¿C). In Phase I, anode-supported SOFC with thin-film YSZ electrolytes and composite cathodes (comprised of the ionic conductor LSGM and electrocatalysts LSM, LSC, and LSCF) were developed, fabricated, and tested. Exceptionally low cathode overpotentials, which resulted in significant increases in SOFC performance, were demonstrated with the use of LSGM-based composite cathodes. Phase II will identify other electrocatalysts for use with LSGM, dope the LSGM to further improve ionic conductivity, and synthesize nanosize powders in order to engineer the desired cathode microstructure. Commercial Applications and Other Benefits as described by awardee: SOFC, capable of delivering high power density while operating at intermediate temperatures, should have application in both consumer and military sectors including distributed power, transportation, residential, automotive, and portable power. Advantages of SOFC include the ability to operate on various hydrocarbon fuels at high efficiency and with low pollution.