A First‐Principles Study of Anion Doping in LiFePO4 Cathode Materials for Li‐Ion Batteries

Abstract Doping anions into LiFePO 4 can improve the electrochemical performance of lithium‐ion batteries. In this study, structures, electronic properties and Li‐ion migration of anion (F − , Cl − , and S 2− ) doping into LiFePO 4 were systematically investigated by means of density functional theory calculations. Anion substitution for oxygen atoms leads to an expansion of the LiFePO 4 lattice, significantly facilitating Li‐ion diffusion. For Cl − and F − anion doped into LiFePO 4 , the energy barrier of Li‐ion migration gets lowered to 0.209 eV and 0.283 eV from 0.572 eV. The introduction of anions narrows the forbidden band of LiFePO 4 , enhancing its electronic conductivity. This work pays a way towards the rational design of high‐performance lithium‐ion batteries.