Two-Dimensional Transition Metal Phosphides As Cathode Additive in Robust Lithium–Sulfur Batteries

The development of advanced cathode materials able to promote the sluggish redox kinetics of polysulfides is crucial to bringing lithium-sulfur batteries to the market. Herein, two electrode materials: namely, Zr₂PS₂ and Zr₂PTe₂, are identified through screening several hundred thousand compositions in the Inorganic Crystal Structure Database. First-principles calculations are performed on these two materials. These structures are similar to that of the classical MXenes. Concurrently, calculations show that Zr₂PS₂ and Zr₂PTe₂ possess high electrical conductivity, promote Li ion diffusion, and have excellent electrocatalytic activity for the Li-S reaction and particularly for the Li₂S decomposition. Besides, the mechanisms behind the excellent predicted performance of Zr₂PS₂ and Zr₂PTe₂ are elucidated through electron localization function, charge density difference, and localized orbital locator. This work not only identifies two candidate sulfur cathode additives but may also serve as a reference for the identification of additional electrode materials in new generations of batteries, particularly in sulfur cathodes.