New ion conductor of (Ba1-xLax)(2)In2O5+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 orthorh ombic phase was in the range of 0.0 < x less than or equal to 0.3, the tetr agonal 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 temper ature with increasing x and disappeared at the phase boundary between the o rthorhombic 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 s tabilized zirconia. These properties were successfully explained in terms o f disordered oxygen ions.