Structural and defect properties of LiTi2(PO4)3

Abstract

LiTi2(PO4)3 is an attractive electrolyte material in Li-ion batteries' application due to its high ionic conductivity and high chemical stability. Here we employ atomistic simulation based on the classical pair potentials to examine the intrinsic defect processes, Li-ion migration, and solution of various dopants in LiTi2(PO4)3. The Li-Frenkel (0.73 eV) is calculated to be the most favorable defect energy process ensuring the formation of Li vacancies required for the vacancy-assisted Li-ion migration. Long-range three-dimensional lithium vacancy migration was observed with a low activation energy of 0.36 eV, inferring fast Li-ion diffusion. The most favorable isovalent dopants on the Li and Ti sites are Na and Si, respectively. Li interstitials' formation in these materials is favored by doping of Ga on the Ti site. This engineering strategy can be of interest to improve the capacity of LiTi2(PO4)3.