Artificial\nByproduct Coatings through a Sublimated\nSulfur Vapor Reaction to Enhance the Stability of Cathode/Sulfide\nElectrolyte Interfaces

Cathodes in sulfide-based all-solid-state batteries (ASSBs)\ncan\nbe coated with stable materials (such as oxides) to mitigate unfavorable\ninterfacial reactions with the sulfide electrolyte. However, the chemical\npotential difference between these coating materials and the electrolyte\nleads to a nonuniform distribution of Li<sup>+</sup> ions at the interface\nand impedes their mobility. In this study, we create a thin, uniform\nlayer of sulfur-containing byproducts by reacting sublimated sulfur\nvapor with the cathode surface to minimize interfacial side reactions.\nThe cathodes treated with sulfur vapor exhibited better electrochemical\nperformance than pristine cathodes. The electrochemical properties\ncould be further enhanced when the sulfur treatment was combined with\nLi<sub>3</sub>PO<sub>4</sub> coating. The sulfur treatment can enhance\nthe chemical compatibility between the cathode surface and sulfide\nelectrolyte, thereby improving the interfacial stability and facilitating\nLi<sup>+</sup> ion migration during cycling. This study presents a\npromising method for stabilizing the cathode/sulfide electrolyte interface,\npotentially accelerating the practical adoption of ASSBs.