Structure and electrical conductivity of BaCe0.7In0.1A0.2O3−δ (A = Gd, Y) ceramics

BaCe0.7In0.1A0.2O3−δ (A = Gd, Y) ceramics were synthesized by solid state reaction method. The microstructure and electrical properties of BaCe0.7In0.1A0.2O3−δ ceramics were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance analysis at intermediate temperatures of 773–1073 K in different atmospheres. All BaCe0.7In0.1A0.2O3−δ ceramics exhibit a cubic perovskite structure. Relative densities of BaCe0.7In0.1A0.2O3−δ ceramics are above 92%. BaCe0.7In0.1Gd0.2O3−δ and BaCe0.7In0.1Y0.2O3−δ ceramics exhibit an excellent chemical stability against boiling water. The conductivity values of BaCe0.7In0.1Gd0.2O3−δ are higher than those of BaCe0.7In0.1Y0.2O3−δ in both air and dry hydrogen atmospheres. The highest conductivity is 4.6 × 10−2 S cm−1 for BaCe0.7In0.1Gd0.2O3−δ ceramic in air at 1073 K. BaCe0.7In0.1Gd0.2O3−δ ceramic with a conductivity value of 1.0 × 10−2 S cm−1 at 823 K in both air and dry hydrogen atmospheres is considered as a promising alternative for electrolytes of SOFC in view of decreasing the operating temperature and keeping both high conductivity and good chemical stability.