First-principles study of the impact of grain boundary formation in the cathode material LiFePO4

Abstract

Motivated by the need to understand the role of internal interfaces in Li migration occurring in Li-ion batteries, a first principles study of a coincident site lattice grain boundary in LiFePO4 cathode material and in its delithiated counterpart FPO4 is performed. The structure of the investigated grain boundary is obtained and the corresponding interface energy is calculated. Other properties, such as ionic charges and magnetic moments, excess free volume and the lifetime of positrons trapped at the interfaces, are determined and discussed. The results show that while the grain boundary in LiFePO4 has desired structural and bonding characteristics, the analogous boundary in FePO4 needs to be yet optimized to allow for an efficient Li diffusion study.

arXiv comment12 pages, 3 figures, 1 table

References in corpus (4)

• Quantum Monte Carlo Study of a Positron in an Electron Gas
• Energetics and cathode voltages of LiMPO${}_4$ olivines (M = Fe, Mn) from extended Hubbard functionals
• Improved generalized gradient approximation for positron states in solids
• Proposed parameter-free model for interpreting the measured positron annihilation spectra of materials using a generalized gradient approximation