The diffusion Li in rutile was investigated by means of molecular dynamics. Simulations were performed using a model which permitted charge transfer among ions. The ionic charges were calculated dynamically at each time-step using an extended Lagrangian method. An additional Nosé–Hoover chain thermostat was used in order to keep the charges at low temperature, and preventing thermal coupling between the nuclear and charge degrees of freedom. The model yielded reasonable values, for the ionic charges, which were in good agreement with quantum-mechanical calculations for Ti and O; with somewhat smaller values for the Li ions. The simulations revealed an expected 1-dimensional diffusion along channels parallel to the [001] direction, and Li diffusion occurred via jumps between octahedral sites located along these channels. The diffusion coefficient of Li was measured at 300 to 900K, for Li/Ti atomic ratios of up to 0.75. At room temperature, values of up to 1.1 x 10−6cm2/s were recorded for low concentrations. The results showed that increasing the Li concentration caused diffusion to slow significantly, and to exhibit an anomalous non-Arrhenius behavior.

Lithium Diffusion in Rutile Structured Titania. Gligor, F., de Leeuw, S.W.: Solid State Ionics, 2006, 177[26-32], 2741-6