Characteristics of YCoO3-type perovskite oxide and application as an SOFC cathode

摘要

YCoO3 is discussed as a novel cathode material for solid oxide fuel cells (SOFCs). One of the major issues for SOFC development is the side reactions that occur at the electrode and electrolyte interfaces. Characteristics such as the phase stability, reactivity against YSZ, electrical conductivity, and thermal expansion coefficients (TECs) of YCoO3 were investigated. YCoO3 was produced by the sol-gel method below 975 degrees C, and the fewest impurities were observed at a Y molar ratio of 0.96 (YCO-096). YCO-096 did not react significantly with the YSZ electrolyte when fired at 975 degrees C for 1 h. The main charge carrier of YCO-096 was confirmed to be electron-holes, h(+), and the maximum conductivity was estimated to be 700 S cm(-1) at 900 degrees C. The TECs of YCO-096 were in the range of 16.5-44.2 x 10(-6) degrees C-1 from room temperature to 900 degrees C. The YCO-096 cathode was stable in the YSZ electrolyte SOFC. Oxygen defects formed at the surfaces of particle YCO-096 were considered to significantly improve the cathodic performance.