The potential application of VS2 as an electrode material for Mg ion battery: A DFT study

Highlights: • DFT for prediction of three types of VS₂ as electrode materials for MIBs. • Investigation of the adsorption, charge transfer, bond stability of Mg on the VS₂. • M-VS₂ can be employed as anode, while D-VS₂, B-VS₂ can be used as cathode for MIBs. Herein, by means of first-principle calculations based on density functional theory (DFT), the electrochemical properties of monolayer VS₂ (M-VS₂), double-layer VS₂ (D-VS₂) and bulk VS₂ (B-VS₂) as electrode materials for Mg-ion batteries (MIBs) were comprehensively explored. The computation results reveal that Mg atom can strongly bind with the three different forms of VS₂. All of the Mg adsorbed VS₂ systems demonstrate metallic characteristics, which indicates a good electronic conductivity. In addition, crystal orbital hamiltonian population shows that the stability of V-S bond is weakened after adsorption of Mg atom. The low diffusion barriers of Mg give rise to the high rate performance of VS₂ in MIBs. More interestingly, the three types of VS₂ display same storage ability for Mg cations, which can adsorb 0.5 Mg atoms for VS₂, producing maximum theoretical capacity 233 mA h g⁻¹ for MIBs. The average working voltages results suggest that M-VS₂ can be employed as anode materials, while D-VS₂, B-VS₂ can be used as cathode materials for MIBs.