Solid oxide fuel cells with electrolytes prepared via spray pyrolysis

Fuel cells utilizing thin electrolyte films deposited onto a prefabricated anode support using spray pyrolysis were tested. Spray pyrolysis allows to prepare thin electrolytes with low ohmic losses and thereby to reduce the operating temperature of solid oxide fuel cells (SOFCs) while maintaining high power output. The electrolyte films consisted of a layer of 8 mol% yttria-stabilized zirconia (YSZ) and a layer of ceria 10 mol% yttria solid solution (CYO). Both were deposited by spray pyrolysis onto NiO–YSZ self-supporting anode substrates. The cells were operated using hydrogen as fuel and air as oxidant at temperatures of 600–800 °C and exhibited an open circuit voltage of 1.01 V at 720 °C indicating a dense and crack-free electrolyte film. High power density in excess of 750 mW/cm2 was provided by cells with a 600 nm thin YSZ/CYO bilayer electrolyte at 770 °C. Cells containing the bilayer electrolytes were operated for over 450 h at 720 °C with tolerable degradation. Good performances of cells with more than two layers of different electrolytes were achieved at 700 °C but considerable degradation was observed. Spray parameters such as deposition temperature showed an effect on cell performance.