The cubic 10Sc1CeSZ (10 mol% Sc 2 O 3 –1 mol% CeO 2 –89 mol% ZrO 2 ) was prepared by controlling the concentration of the urea varied from 0.4 to 0.6 mol/L in the hydrothermal process. XRD results depict that the 10Sc1CeSZ blocks have a stable cubic phase structure at room temperature after sintering at 1150–1450 °C. SEM characterization of the fracture surface of the 10Sc1CeSZ blocks shows that the grain size increases from 0.3 to 8 μm during heat treatment up to 1150–1450 °C, correspondingly, the relative densities increase from 98.3% to 99.7%. The impedance spectra measured at 300 °C reveal that the grain boundary resistance reduces with the increase of sintering temperature. Impedance analysis results show that the 10Sc1CeSZ block sintered at 1450 °C for 4 h has the highest total ionic conductivity of 0.137 S cm − 1 at 800 °C.
