Lithium Ion Conductivity in A-site Deficient Perovskites Sr_0.5La_0.05Li_0.35□_0.1Ti_0.5Ta_0.5O₃ and Sr_0.35La_0.15Li_0.35□_0.l5Ti_0.5Ta_0.5O₃

Abstract

A-site deficient perovskites Sr_0.5La_0.05Li_0.35□_0.1Ti0.5Ta_0.5O₃ and Sr_0.35La_0.15Li_0.35□_0.15Ti_0.5Ta_0.5O₃ were synthesized, and their structures and lithium ion conductivities were investigated. Both compounds have cubic symmetry (space group; Pm3m) and the A- and B-site ions are randomly distributed. The ionic conductivities for the bulk part at 300 K are 6.8×10^-4 S em^-1 for Sr_0.5La_0.05Li_0.35□_0.1Ti_0.5Ta^0.5O₃ and 7.2×10^-4 S cm^-1 for Sr_0.35La_0.15Li_0.35□_0.15Ti_0.5Ta_0.5O₃, respectively, which are higher than that of Sr_0.5Li_0.5Ti_0.5Ta_0.5O₃ (5.5×10^-4 S em^-1). The ionic conduction of their compounds was found to be based on the vacancy process as was observed for other perovskite-type lithium ion conductors.