Exploring the Strain-Enhanced Li-Ion Migration in Li1.33Al0.33Ti1.67(PO4)3 Solid Electrolyte

Solid-state lithium batteries are a promising solution to the next generation of electrochemical energy storage systems due to their large energy storage density and high levels of safety. Particularly, Li1+xAlxTi2–x(PO4)3 (LATP) has been recently attracting significant interest as it exhibits high Li-ion mobility and ionic conductivity. In addition to the doping level, the electrical properties of LATP can be altered by mechanical deformations. In this work, the strain effect on the Li-ion conductivity in Li1.33Al0.33Ti1.67(PO4)3 (LATP-0.33) was investigated using classical molecular dynamics (MD) and density functional theory (DFT) calculations. It is shown by MD that the ionic conductivity of LATP can be significantly enhanced by the application of appropriate mechanical strains. Further DFT calculations have been performed to study the mechanism for the strain-enhanced conductivity of Li ions in LATP. It is illustrated that the applied strain can lead to the reduced interactions of Li ions with the neighboring O atoms in TiO6 along the Li-ion migration pathway and thus enhances the mobility of Li ions in LATP. The strain-induced enhancement of Li-ion migration in LATP as revealed in this work can be helpful for designing and engineering solid-state lithium batteries.