Large-Scale synthesis of metal halide doped Li7P2S8X solid electrolytes and their compatibility with organic solvents and binders

Solid state inorganic ceramic electrolytes have garnered considerable attention for the development of all solid-state batteries (ASSBs) due to their high safety, thermal stability, and energy density. Despite extensive studies on the physio-electrochemical characteristics of these solid electrolytes, it is essential to evaluate their stability against organic solvents and binders for successful large-scale commercialization. In this study, we optimized the large-scale synthesis of SnCl₂ doped Li₇P₂S₈I (LTPSIC) solid electrolyte using a high energy ball milling process. The LTPSIC solid electrolyte, treated with various polar and non-polar organic solvents and polymeric binders, demonstrated ionic conductivity comparable to that of the untreated LTPSIC solid electrolyte. Moreover, the treated LTPSIC solid electrolytes-maintained stability with a lithium metal anode and showed a critical current density nearly identical to that of the untreated LTPSIC solid electrolyte. Finally, we assembled an all-solid-state lithium battery (ASSB) using the treated LTPSIC solid electrolyte sheet and studied its galvanostatic charge–discharge characteristics. The resulting ASSB displayed an initial specific capacity of 153.3 mAh g⁻¹ with a coulombic efficiency of 72.3 % at a 0.1C-rate. The present work enables the large-scale fabrication of LTPSIC solid electrolytes with high ionic conductivity and stability against organic solvents and polymeric binders. This advancement allows slurry-based processing, a critical step toward roll-to-roll manufacturing of ASSBs.