Research on the adsorption mechanism and the effect of sulfur-inhibiting shuttle of lithium polysulfides on Mn3O4 for lithium-sulfur batteries

The shuttle effect of lithium polysulfides poses a significant challenge to the practical application of lithium-sulfur batteries. When the adsorption energy of a material is greater than that in the solvent, the anchoring effect of the material inhibits the shuttle effect. In this study, first-principles calculations were employed to investigate the ion-relaxation and electronic structures of the adsorption material Mn3O4, Li2Sx molecules, and the surface model of Li2Sx adsorption on Mn3O4. The mechanism of Mn3O4 adsorption to Li2Sx molecules and its role in inhibiting the sulfur shuttle were elucidated through the analysis of adsorption energies, changes in Li-O and S-Mn bonds during the adsorption process, and the charge transfer between Li2Sx molecules and surface atoms. The comprehensive analysis conducted at molecular, atomic, and electronic levels provides valuable insights into the adsorption process. It was observed that O and Mn sites co-adsorb at both long and short bridge sites, with the long bridge sites demonstrating higher effectiveness in adsorbing Li2Sx. The study proposes that incorporating Mn3O4 into the battery separator can effectively adsorb Li2Sx, thereby suppressing the shuttle effect, owing to the robust Li-O and S-Mn interactions identified in the analysis. This approach holds promise for enhancing the performance of lithium-sulfur batteries by mitigating the detrimental impact of the shuttle effect. © 2024