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

摘要

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.