Investigations on V₂C and V₂CX₂ (X = F, OH) monolayer as a promising anode material for Li Ion batteries from first-principles calculations

First-principles calculations are performed to study the electronic properties and Li storage capability of V₂C and its corresponding fluoride and hydroxide. We find that the V₂C monolayer is metallic with antiferromagnetic configuration, while its derived V₂CF₂ and V₂C(OH)₂ in their the most stable configurations are small-gap antiferromagnetic semiconductors. Li adsorption could enhance the electric conductivity of V₂C fluoride and hydroxide. The bare V₂C monolayer shows fast Li diffusion with low diffusion barrier height and very high Li storage capacity (with theoretical value ∼940 mAh/g), while the passivated F or OH atoms on its surface tend to impede Li diffusion and largely reduce the Li storage capacity. Moreover, the average intercalation potentials for V₂C-based materials are calculated to be relatively low. Our results suggest that V₂C monolayer could be a promising anode material for Li-ion batteries.