A computational study on bifunctional 1T-MnS 2 with an adsorption-catalysis effect for lithium-sulfur batteries

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-MS (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 Li S, and the Gibbs free energy barrier of the sulfur reduction reaction based on first-principles calculations. Our results show that the sulfiphilicity of 1T-MS plays an important role in the adsorption behavior of short-chain sulfur species, in addition to lithiophilicity. Remarkably, among the five 1T-MS materials, our results confirm that 1T-TiS and 1T-VS show excellent adsorption-catalysis performance and it is predicted that 1T-MnS is an even better candidate catalyst to inhibit the shuttle effect and accelerate delithiation/lithiation kinetics. Moreover, the outstanding performance of 1T-MnS persists in a solvent environment and under strain modulation. Our results not only demonstrate that 1T-MnS 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.