Structure and electrical conductivity of BaCe(0.7)In(0.1)A(0.2)O(3-delta) (A = Gd, Y) ceramics

BaCe(0.7)In(0.1)A(0.2)O(3-delta) (A = Gd, Y) ceramics were synthesized by solid state reaction method. The microstructure and electrical properties of BaCe(0.7)In(0.1)A(0.2)O(3-delta) 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 BaCe(0.7)In(0.1)A(0.2)O(3-delta) ceramics exhibit a cubic perovskite structure. Relative densities of BaCe(0.7)In(0.1)A(0.2)O(3-delta) ceramics are above 92%. BaCe0.7In0.1Gd0.2O3-delta and BaCe0.7In0.1Y0.2O3-delta ceramics exhibit an excellent chemical stability against boiling water. The conductivity values of BaCe0.7In0.1Gd0.2O3-delta are higher than those of BaCe0.7In0.1Y0.2O3-delta in both air and dry hydrogen atmospheres. The highest conductivity is 4.6 x 10(-2) S cm(-1) for BaCe0.7In0.1Gd0.2O3-delta ceramic in air at 1073 K. BaCe0.7In0.1Gd0.2O3-delta ceramic with a conductivity value of 1.0 x 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. (C) 2011 Elsevier Ltd. All rights reserved.