A study was made of the results of a neutron powder diffraction study of the La0.62Li0.16TiO3 perovskite that determined the diffusion path of Li cations at room temperature. At 77K, the Li cations were located at the 2c site (Wycoff notation of the Cmmm space group) on the (002) La deficient layer, while, at room temperature, they were spread over a wide area and migrate following the 2c-4f-2c or 2c-2d-2c tie line on the (002) layer. The probability density of Li cations had a minimum between the 2c and 4f or between the 2c and 2d positions on the diffusion path in contrast to the previous reports where the bottleneck was thought to be located at the 2c, 2d, and 4f positions. On the basis of the present structural model, the Li-cation conductivity was explained in terms of a 2-dimensional bond-percolation model for Li-cation diffusion. It was found that the vacancy at the La site was essential for Li-cation conduction.

Crystal Structure and Diffusion Path in the Fast Lithium-Ion Conductor La0.62Li0.16TiO3. M.Yashima, M.Itoh, Y.Inaguma, Y.Morii: Journal of the American Chemical Society, 2005, 127[10], 3491-5