Preparation, characterization and thermo electrical properties of co-doped Ce0.8 − xSm0.2CaxO2 − δ materials

The present paper deals with the preparation, characterization, thermal expansion and the electrical conductivity of co-doped ceria Ce0.8 − xSm0.2CaxO2 − δ (0.0 ≤ x ≤ 0.1) electrolyte materials. These compositions were prepared through the sol–gel method. The phase identification and morphology was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The lattice parameter was determined by X-ray powder diffraction. The thermal expansion was measured using dilatometric technique in the temperature range 30–1000 °C. It was observed that the thermal expansion increased linearly with increasing temperature for all the samples. The electrical conductivity was studied using two-probe impedance spectroscopy and it was observed that the composition Ce0.78Sm0.2Ca0.02O2 − δ showed higher electrical conductivity and lower activation energy (0.79 ± 0.02 eV) than samarium-doped ceria (SDC) at 700 °C. This composition is thus a possible candidate for use as electrolyte in intermediate temperature solid oxide fuel cells (IT-SOFC).