Optimization of the Ceria Interlayer for Co-Containing Cathodes

摘要

Co-containing perovskite cathodes have been studied as the promising replacement for the typically used (La,Sr)MnO3 cathode in lower-temperature operation of SOFCs, except that they react with the zirconia-based electrolyte to form the resistive interfacial phases. There have been several reports on the reaction-reducing effect of inserting the ceria-based interlayer between the Co-containing cathode and the zirconia electrolyte, but they are not sufficient for elucidating the underlying reaction mechanism and suggesting the most appropriate fabrication condition of the interlayer. In this study, the interfacial reaction mechanism regarding Sr diffusion from the cathode was investigated in cells with the Co-containing cathode, the zirconia electrolyte, and the ceria interlayer. Based on the mechanism, various fabrication methods and conditions were applied to the interlayer, in order to find the correlation between its microstructure and diffusion-blocking property and propose the best fabrication technology.