Preparation and characterization of Ce1−x(Gd0.5Pr0.5)xO2 electrolyte for IT-SOFCs

The Ce1−x(Gd0.5Pr0.5)xO2 (x = 0–0.24) compositions were synthesized through the sol–gel process followed by low temperature combustion. X-ray diffraction data analysis showed that all the samples exhibit a cubic structure with single phase. The lattice parameter was calculated by rietveld refinement of XRD patterns. Dense ceramics were prepared by sintering the pellets at 1300 °C. The relative density of the samples was over 98%. The surface morphology was studied by Scanning electron microscopy (SEM). Chemical composition was analyzed by Energy dispersive spectroscopy (EDX). A.C. impedance spectroscopy measurements were carried out to study the grain, grain boundary and total ionic conductivity of co-doped ceria samples in the temperature range 150–700 °C. The Ce0.84(Gd0.5Pr0.5)0.16O2 composition showed highest grain ionic conductivity i.e., 1.059 × 10−2 S/cm at 500 °C which is 11.5% higher than the Ce0.9Gd0.1O2 (with an activation energy 0.62 eV). At intermediate temperatures, the Ce1−x(Gd0.5Pr0.5)xO2 materials were found to be ionic in nature.