Fabrication of Sm 0.5Sr 0.5CoO 3− δ−Sm 0.1Ce 0.9O 2− δ cathodes for solid oxide fuel cells using combustion CVD

Abstract

This study aims at optimization of major processing parameters of combustion CVD for solid oxide fuel cell (SOFC) electrode fabrication. A series of depositions were performed to reveal the correlation between process parameters and the microstructures observed as well as the interfacial resistances between electrodes and electrolytes. It is found that deposition temperature has a significant impact on electrode morphology as well as interfacial resistance. Deposition temperatures lower than 1000 °C resulted in cathodes with very high interfacial resistances while temperatures higher than 1400 °C led to over-densification. Thus for deposition of Sm 0.5Sr 0.5CoO 3− δ (SSC)−Sm 0.1Ce 0.9O 2− δ (SDC) composite cathodes on Gd 0.1Ce 0.9O 2− δ (GDC) electrolyte, the performance is optimized at deposition temperatures between 1200 and 1300 °C. Cathodes of 25–40 μm thick can be deposited onto GDC pellets in 5−10 min using a 0.05 M precursor solution. The interfacial polarization resistances between SSC-SDC electrode and YSZ electrolyte were two orders of magnitude higher than those between the electrode and GDC electrolyte.