Sm0.2Ce0.8O1.9/Y0.25Bi0.75O1.5 bilayered electrolytes for low-temperature SOFCs with Ag-Y0.25Bi0.75O1.5 composite cathodes

Y0.25Bi0.75O1.5 (YSB) thin films of 6 μm thick were deposited on Sm0.2Ce0.8O1.90 (SDC) electrolytes via a DC magnetron sputtering technique to form highly conductive bilayered electrolytes for low-temperature solid oxide fuel cells (SOFCs). Single cells with Ni-SDC as the anode, Ag-YSB composite as the cathode, and monolayer SDC and bilayered SDC/YSB as the electrolyte were fabricated and tested using humidified H2 as the fuel and ambient air as the oxidant. Both open circuit voltages and power densities were improved by using the bilayered electrolytes. A peak power density of 223 mWcm− 2 was obtained at 500 °C. Area specific polarization resistances of the Ag-YSB electrodes were also investigated using symmetrical cells with SDC and YSB as the electrolyte.