Insight into the Anchoring Effect of Two‐Dimensional TiX₂ (X = S, Se) Materials for Sodium–Sulfur Batteries: A First‐Principles Study

Abstract

In this paper, a monolayer of TiX 2 (X = S, Se) is used to suppress the shuttle effect of polysulfides, thereby accelerating the kinetic process of lower-order polysulfides. The results show that the adsorption energies of the studied TiX 2 for Na 2 S n are all better than those of common electrolytes, and the effect of adsorption on the structure of Na 2 S n is negligible. The calculated results show that the anchoring behavior of TiX 2 to Na 2 S n has no effect on the metallic properties of pristine TiX 2 . On the other hand, the introduction of this material can reduce the diffusion barrier energy of Na 2 S and improve the utilization rate of sulfur more effectively. In conclusion, TiX 2 has suitable adsorption strength, enhances electrical conductivity, and promotes the oxidative decomposition process of polysulfides. It can be theoretically demonstrated that TiS 2 is better than TiSe 2 in improving the performance of sodium-sulfur batteries and is more suitable as an anchoring material (AM) for sodium-sulfur batteries.