A neutron powder diffraction study was made of the La0.62Li0.16TiO3 perovskite in order to determine the diffusion path of Li cations at room temperature. At 77K, the Li cations were located at the 2c site (of the Cmmm space group) on the (002) La deficient layer. At room temperature, they were spread over a wide area and migrated along the 2c-4f-2c or 2c-2d-2c tie-lines on the (002) layer. The probability density of Li cations exhibited a minimum value between the 2c and 4f or between the 2c and 2d positions on the diffusion path; in contrast to previous reports, where the bottleneck was said 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