FAST OXIDE-ION CONDUCTION IN INTERGROWTH STRUCTURES

Investigation of intergrowth structures consisting of perovskite blocks alternating with other blocks along the c-axis has been found to offer a novel "doping strategy" for fast oxide-ion conduction at significantly lower temperatures. Barium indium oxides such as Ba3In2MO8 (M=Zr, Hf and Ce) have an intergrowth structure in which two octahedral layers alternate with one tetrahedral layer along the c-axis. These oxides exhibit remarkable O2--ion conduction at 400-degrees-C with a low activation energy E(a) less-than-or-similar-to 0.6 eV. A variety of substitutions on the vanadium site in Bi4V2-yMyO11-delta has led to the identification of fast O2--ion conduction at y almost-equal-to 0.2 for M=Ti and Nb in addition to that found with M=Cu by a French group. Observation of fast oxide-ion conduction at T<400-degrees-C brings renewed interest to the field of oxide-ion electrolytes.