Theoretical study on strain engineering for improving the performance of TiS2 monolayer as cathode material for lithium-sulfur batteries

As an effective method for modulating electrochemical characteristics, strain engineering is employed in this study to optimize the properties of TiS₂ monolayer. Through first-principles calculations, we examine the influence of biaxial compressive strain on their structural integrity, electronic structure, and catalytic properties relevant to lithium-sulfur (Li-S) batteries applications. The results reveal that compressive strain enhances the electrical conductivity by increasing band overlap near the Fermi level and strengthens the adsorption of lithium polysulfides (LiPSs) within a moderate binding range. At −5 % strain, the sulfur reduction reaction (SRR) barrier from Li₂S₄ to Li₂S₂ decreases from 0.32 eV to 0.18 eV, while the decomposition energy of Li₂S and the diffusion barrier of Li⁺ are also significantly reduced. These improvements in both catalytic activity and polysulfide anchoring under moderate compressive strain suggest that TiS₂ is a promising candidate for use in next-generation Li-S battery cathodes.