Abstract
Scandia stabilized zirconia has the highest ionic conductivity of zirconia based electrolytes. From the scandia-zirconia phase diagram 6-9 mol% scandia is cubic at room temperature, however, the cubic phase transforms to tetragonal with annealing at elevated temperatures. Increasing the scandia concentration to 10-12 mol% results in a stable cubic phase at above 600ºC, however, the stable phase at room temperature is rhombehedral. An addition of a third oxide can be used to suppress the rhombehedral to the cubic phase change to below room temperature. This study was a comparison of CeO2-doped and Bi2O3-doped 10 mol% scandia stabilized zirconia (10ScSZ) by X-ray diffraction and AC impedance spectroscopy. For both compositions pellets sintered at 1200ºC and 1300ºC resulted in a cubic phase. Both CeO2 and Bi2O3 additions stabilized the cubic phase at room temperature. 2 mol% Bi2O3 + (Sc2O3)0.10 (ZrO2)0.90 pellets had a comparable conductivity when sintered at 1300{degree sign}C and 1400{degree sign}C, and a lower conductivity when sintered at 1500{degree sign}C compared to (Sc2O3)0.10Ce0.01(ZrO2)0.89.