The potential application of VS_2 as an electrode material for Mg ion battery: A DFT study

摘要

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.