The Li atom positions are calculated in Li x TiO2 anatase, by means of periodic density functional theory calculations, followed by the predictions of the energy barriers for the mobility of Li atoms, done for the first time for a range of Li concentrations (x <0.5). A fivefold-coordinated environment was confirmed for the Li atoms in the empty octahedral sites in titanate (orthorhombic) Li x TiO2 structures. For the low Li concentration structures (anatase) a fourfold-coordination was found for the Li atoms. The energy barrier to move a Li atom from one octahedral site to a neighboring one is found to converge for x value higher than 0.5–0.6eV. The barrier used to calculate the hopping rate was found to decrease with increasing Li concentration.