Spray pyrolysis of electrolyte interlayers for vacuum plasma-sprayed SOFC

The effects of gadolinia-doped ceria (CGO, Ce_0.8Gd_0.2O_1.9-x) and yttria-doped zirconia (8YSZ, Zr_0.92Y_0.08O_2-x) interlayers prepared by spray pyrolysis between vacuum plasma-sprayed 8YSZ electrolytes (8YSZ-VPS) and screen-printed (La_0.8Sr_0.2)_0.98MnO₃ cathodes (LSM) on the power output of solid oxide fuel cells (SOFC) are investigated. Amorphous thin films are deposited and then converted to nanocrystalline electrolyte-cathode interlayers during the first heat-up cycle of a SOFC to the operating temperature. CGO thin films between the YSZ plasma-sprayed electrolyte and the LSM cathode increased the power output by more than 20% compared to cells without interlayers, whereas YSZ films degraded the power output of cells. It is assumed that CGO improves the charge transfer at the electrolyte-cathode interface and that the CGO layer prevents the formation of undesirable insulation of La-zirconate at the interface 8YSZ/LSM.