Anisotropic Diffusion of a Charged Tritium Interstitial in Li2TiO3 from First-Principles Calculations

Li${}_{2}$TiO${}_{3}$ is the most promising breeder material for a fusion reactor based on the lithium-deuterium nuclear reaction. Unfortunately, the kinetics of tritium release from this oxide is poorly understood, both experimentally and theoretically. This study uses density functional theory to analyze locally stable crystal sites and various diffusion paths for interstitial T${}^{+}$ in Li${}_{2}$TiO${}_{3}$. Strongly anisotropic diffusion of tritium along different crystalline directions is revealed. The results provide a first-principles theoretical guide for experiments, as well as key energetic parameters for further kinetic modeling and simulations.