Atomistic investigation of Li+ diffusion pathways in the olivine LiFePO4 cathode material

Abstract

We present a molecular dynamics study of Li⁺ jump frequencies in the olivine LiFePO₄ cathode material. Besides the principal diffusion pathways along [010] we also find relevant particle motion along [001]. We produce a very detailed landscape of many-particle motion, consistent with the complex nature of the diffusion phenomenon. Patterns of Frenkel defect creation and migration are described in stoichiometric, defect-free LiFePO₄ as well as in the presence of antisite defects. We stress the importance of many-particle Li hoppings to capture diffusion and transport processes in detail.