The influence of Cl doping on the structural, electronic properties and Li-ion migration of LiFePO4: A DFT study

Modifying LiFePO4 with anion doping can improve the electrochemical performance of lithium-ion batteries. Here, theoretical work of Cl-doped LiFePO4 is performed using density functional theory (DFT) to calculate the structural, electronic properties and Li-ion migration. The substitution of chlorine for oxygen has expanded the LiFePO4 lattice due to the larger Cl- ions ionic radii. Cl doping also contributes to the band gap reduction, indicating the material exhibits better electronic conductivity. The migration energy for Li-ion migration has decreased from 0.838 eV to 0.709 eV upon Cl doping. These doping effects imply that LiFePO4 has improved the electrochemical performance of lithium-ion batteries.