High Oxide Ion Conductivity of (Ba1-x-ySrxLay)InO2.5+y/2 Members Derived from the Ba2In2O5 System
We have discovered a high oxide ion conductor within the perovskite-type (Ba1-x-ySrxLay)InO2.5+y/2 solid-solution system. The system was derived from brownmillerite-type Ba2In2O5, which possessed a ordered oxide ion vacancies. When we doped La3+ into the Ba site, the vacancy changed to a disordered state. The oxide ion conductivity increased with the amount of doped La3+, reaching a maximum value of 0.12 (S/cm) at 800 oC in (Ba0.3Sr0.2La0.5)InO2.75, a level exceeding that of yttria-stabilized zirconia. The oxide ion conductivity of this system was strongly dependent on the unit cell free volume, which appears to be the key parameter governing oxide ion mobility.
David J. Fisher
K. Kakinuma et al., "High Oxide Ion Conductivity of (Ba1-x-ySrxLay)InO2.5+y/2 Members Derived from the Ba2In2O5 System ", Defect and Diffusion Forum, Vols. 242-244, pp. 159-168, 2005