New ion conductor of (Ba1-xLax)2In2O5+x

The structural characterization, thermogravimetric analysis and electrical properties for solid solution system, (Ba1-xLax)(2)In2O5+x with perovskite-type structure were investigated. X-ray diffraction showed that the orthorhombic phase was in the range of 0.0 < x less than or equal to 0.3, the tetragonal phase 0.3 < x less than or equal to 0.5, and the cubic phase 0.5 < x. The sharp transition of electrical conductivity shifted to a lower temperature with increasing x and disappeared at the phase boundary between the orthorhombic and tetragonal phases. This perovskite-related oxide exhibited a pure oxide-ion conduction over the oxygen partial pressure range of 1 atm to 10(-)3.5 atm, and the electrical conductivity reached the value of 1.6.10(-1) (S cm(-1)) at 1073 K, which was nearly equal to that of the yttria stabilized zirconia. These properties were successfully explained in terms of disordered oxygen ions.