Insight into the Anchoring Effect of Two-Dimensional TiX2 (X = S, Se, Te) Materials for Lithium-Sulfur Batteries: A DFT Study

It is desirable to develop suitable anchoring materials to refrain the notorious shuttle phenomenon in lithium-sulfur (Li-S) batteries. Two-dimensional transition metal dichalcogenides (2D TMDs), especially TiS 2 , with excellent physicochemical properties have attracted much attention. Here, in this work, density functional theory (DFT) computations were performed to systematically explore the adsorption behaviors of lithium polysulfides (LiPSs) over TiX 2 (X = S, Se, Te) monolayer. It is concluded that TiS 2 shows the best anchoring effect owing to the strongest adsorption energy. And it’s found that the intrinsic structures of LiPSs after adsorption could be preserved by calculating the decomposition energy. Moreover, the low diffusion energy barrier of Li 2 S on TiS 2 surface is expected to accelerate the kinetics during the charge/discharge process. Based on a series of calculations and discussion, we can theoretically demonstrate that TiS 2 , as an anchoring material, has advantages over TiSe 2 and TiTe 2 in enhancing Li-S batteries performance.