Abstract
Both the shuttle effect of long-chain polysulfides and the non-uniform deposition of short-chain polysulfides upon the surface of a cathode will reduce the usage rate of active materials and restrict the large-scale production of lithium-sulfur (Li-S) batteries. Here, a first-principles calculation was employed to systematically determine and investigate the potential application of VX (X = S, Se) as an anchoring material for Li-S batteries. The adsorption energy, density of state, charge transfer, and difference-charge density were calculated. It is apparent that there are charges transfer between Li2S and VX, and the chemical-adsorption energies of Li2S on VX are strong. The interaction between the 5 atom of Li2S and the surface V atom of VX is the origin of anchoring; moreover, the diffusion behavior of Li ions on the VX surface was studied, and the diffusion barrier was found to be relatively low. The results demonstrate that VS and VSe may act as excellent anchoring materials for high-efficiency Li-S batteries.
NSTL
Elsevier