Atomic mechanical properties of structure and diffusion in the MoO₃ anode materials during lithiation

In order to realize MoO₃ as an anode material in lithium ion batteries, it is important to understand the atomic level mechanisms of MoO₃ structures evolution during lithiation. A first-principle method is employed to evaluate the volumetric deformation, electronic structure, and Young's modulus during lithiation based on density function theory. The electrochemical insertion of Li ions into MoO₃ anode materials prompts a volumetric deformation along the perpendicular direction. Moreover, we analyzed the projected density of states during lithiation for MoO₃. The band gap will vanish at high enough Li concentration, the electron will dope into Mo atoms by Li interaction. In addition, the migration energy barriers of lithium ions along the z-direction are the lowest among other pathways, while a large deformation caused by lithiation remained in the MoO₃ materials. In particular, the Young's modulus of the MoO₃ anode materials increased during lithiation, but the large mechanical strength can sustain this. Those results may reveal the mechanism of structural transition from the MoO₃ to Li₂MoO₃ and provide some valuable mechanical understanding of Li_xMoO₃ materials in lithium ion batteries.