MD Calculation Studies of Residence Site and Diffusion Path of Li Ions in Perovskite-Type (LaLi)TiO₃

Abstract

A computer simulation is performed by a molecular dynamics method to study the structural and dynamical properties in superionic conductor La 4/3- x Li\(_{3x}\square_{2/3-2x}\)Ti 2 O 6 (\(\square=\text{vacancy}\)), which is the perovskite-type Li ion conductor. At low Li concentrations, Li ions conduct with a two-dimensional motion, while Li ions diffuse with a three-dimensional motion at high Li ion concentrations. The partial distribution function for Li–Ti and the diffusion paths of Li ions suggest that Li ions stay for a long time at off-site positions which are 2.7 Å away from a body-centered Ti ion. The Li ion concentration dependence of σ is in approximate agreement with experiments.