Thermal and electrical properties of Ce0.8-x Pr x Sm0.2O2-δ electrolyte materials for IT-SOFC applications

Abstract

Praseodymium and samarium co-doped ceria-based electrolyte materials Ce0.8-x Pr x Sm0.2O2-δ (0≤ x ≤0.06) were prepared by using the sol–gel method. The phase identification and morphology were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The thermal expansion properties were studied by using a dilatometric technique, and it was observed that the thermal expansion coefficient (TEC) varies linearly with temperature for all the samples in the temperature range 30–1000 °C. The electrical conductivity was studied using impedance spectroscopy, and it was observed that the Ce0.74Pr0.06Sm0.2O2-δ composition showed higher electrical conductivity and lower activation energy, and constant phase element (CPE) equivalent circuit was fitted at 450 °C. This composition, because of its unique properties, may find applications in the intermediate-temperature solid oxide fuel cell (IT-SOFC) as an electrolyte.