A computational study on bifunctional 1T-MnS2 with an adsorption-catalysis effect for lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries are promising rechargeable energy storage systems with a high energy density, environmental friendliness and low cost. However, the commercialization process of Li–S batteries has been seriously hindered by the shuttling of lithium polysulfides (LiPSs) and the sluggish kinetics of conversion reaction among sulfur species. In this work, the adsorption-catalysis performance of five transition metal disulfide 1T-MS₂ (M = Mn, V, Ti, Zr, and Hf) surfaces is investigated by evaluating the adsorption energy of sulfur species, Li-ion diffusion energy barrier, decomposition energy barrier of Li₂S, and the Gibbs free energy barrier of the sulfur reduction reaction based on first-principles calculations. Our results show that the sulfiphilicity of 1T-MS₂ plays an important role in the adsorption behavior of short-chain sulfur species, in addition to lithiophilicity. Remarkably, among the five 1T-MS₂ materials, our results confirm that 1T-TiS₂ and 1T-VS₂ show excellent adsorption-catalysis performance and it is predicted that 1T-MnS₂ is an even better candidate catalyst to inhibit the shuttle effect and accelerate delithiation/lithiation kinetics. Moreover, the outstanding performance of 1T-MnS₂ persists in a solvent environment and under strain modulation. Our results not only demonstrate that 1T-MnS₂ is an excellent potential catalyst for high-performance Li–S batteries, but also provide great insights into the adsorption-catalysis mechanism during the cycling process.