Two-dimensional SnP3 monolayer for inhibiting the shuttle effect in lithium-sulfur batteries: A first-principles study

Abstract

The problems of the shuttle effect and sluggish transformation kinetics of lithium polysulfides (LiPSs) severely inhibit the practical application of Li-S batteries. Exploring anchoring materials with catalytic properties is an effective way to overcome these obstacles. In this paper, the electrochemical performance of SnP3 monolayer as an anchoring material is explored by using first-principles calculations. SnP3 monolayer can effectively anchor soluble LiPSs under vacuum and solvent conditions, and provides abundant adsorption sites for anchoring multiple LiPSs. Importantly, the rate-limiting step has changed to the conversion of Li2S8 to Li2S6, suggesting that the monolayer can facilitate the conversion of LiPSs and inhibit their accumulation in the electrolyte. Furthermore, lower decomposition and diffusion barriers of Li2S effectively inhibit the volume expansion of Li-S batteries. Thus, SnP3 monolayer becomes a promising anchoring material with suitable catalytic properties. This work demonstrates the feasibility of SnP3 monolayer as an anchoring material and expands the membership of phosphide family for applications in the field of Li-S batteries.