Effects of oxygen vacancy on the electrochemical properties of γ-V2O5 as cathode material for lithium-ion batteries: a first-principle study

Generating oxygen vacancies is an effective way to improve the lithium-ion storage performance of V2O5. However, the mechanism has not been theoretically investigated. In this study, first-principle calculations were performed to study the effect of oxygen vacancy on electrochemical properties of γ-V2O5 as cathode material for lithium-ion batteries. γ-V2O5 with oxygen vacancy mole fraction of 1.67% shows an open circuit voltage about 0.1 V lower than that of the perfect γ-V2O5. Oxygen vacancies generates gap states, which is beneficial to the electronic conductivity of γ-V2O5 and γ-LiV2O5. In addition, the activation energies for lithium-ion diffusion along [010] in both γ-V2O5 and γ-LiV2O5 are increased by oxygen vacancy, which might lead to the decrease of diffusion coefficient. Our results will provide guidance for further improving the lithium-ion storage performance of γ-V2O5.