Interface Analysis of Complex Oxide Ceramics in Electrolyte Supported Solid Oxide Fuel Cell

Solid Oxide Fuel Cells (SOFC) offer electrochemically generated sources of electricity using oxygen ion transport at elevated temperatures. Analysis of materials used in SOFC using electron microscopy provides insights of foreseeable chemical reactions that govern the performance of the fuel cell. Materials used in SOFC can be divided into four categories; anode, cathode, electrolyte and interconnects/sealants. Materials at anode satisfy the requirement of either pure electronic conduction or appropriate balance of mixed electronic/ionic conduction. The electrolyte is an oxide ceramic material with fluorite structure and a typical combination of group 4 transition metal and oxygen. The oxygen vacancies in fluorite oxide structure can be increased by replacing group 4 element with a transition metal (with matching ionic radii) either from group 3 or lanthanoids category. Cathode is composed of perovskite oxide ceramic structure with ABO3 configuration. Oxygen vacancies can be created by doping group 2 element with 2+ valence state (and matching ionic radii) at A or B site. The oxygen vacancies at cathode promote oxygen intake and mobility at high temperatures. To avoid direct gas mixing of hydrogen and oxygen at high temperatures, anode and cathode are isolated during active fuel cell operation.