Computational insights into the application of V2NS2 monolayer as anode material for Li/Na/K alkali metal-ion batteries

Abstract

The electrochemical performance of Li/Na/K alkali metal ions on the monolayer V₂NS₂ battery electrode are investigated based on first-principles calculations. The V₂NS₂ monolayer shows excellent electrical conductivity, and the good adsorption effect on alkali metal ions (−1.48 eV to −2 eV) indicates a stable interaction between the alkali metal ions and the substrate. The extremely low diffusion barriers for Li/Na/K on V₂NS₂ (0.198 eV, 0.073 eV, 0.045 eV) suggest that it appears rapid ionic diffusion capabilities and electrode reversibility on the V₂NS₂ monolayer. Furthermore, the average OCV for alkali metal ions on the V₂NS₂ monolayer is predicted to range from 0.38 V to 0.86 V, ensuring the safety of the electrode. The theoretical capacities of 1191.2 mAh/g, 495.8 mAh/g, 198.5 mAh/g is obtained for Li/Na/K adsorption on the V₂NS₂ monolayer, respectively. The hydrophilicity of V₂NS₂ is conducive to the combination with aqueous binders during the preparation process. Slight O-doped of V₂NS₂ can also enable the substrate material to maintain good electrical conductivity and diffusion properties. In summary, the intriguing electrochemical properties of V₂NS₂ as an anode material for Li/Na/K alkali metal-ion batteries are expected to provide a theoretical impetus for the advancement of secondary battery technology.