Study on Solvent Compatibility and Electrochemical Performance of Sulfide-Based All-Solid-State Batteries Using Wet Processing

Sulfide all-solid-state batteries are considered a key development area for next-generation energy storage systems thanks to their high energy density and excellent safety profile. However, the compatibility and interaction mechanism between sulfide electrolytes and organic solvents are unclear, which limits the application and large-scale development of wet electrode processes. This study focuses on Li6PS5Cl (LPSC) and investigates how three solvents─isoamyl acetate, n-butyl isobutyrate, and N-methylpyrrolidone─affect the electrochemical performance and dispersion behavior of LPSC, using a combination of experiments and simulations. The results show that LPSC has the highest diffusion coefficient (9.08 × 10–7 cm2 s–1) and ionic conductivity (5.12 × 10–3 S cm–1) in isoamyl acetate, indicating good compatibility. Cathodes prepared using this solvent via the wet process achieved a first-cycle capacity of over 200 mAh g–1 at 0.33C, with a Coulombic efficiency of more than 99.5%. These cathodes retained a specific capacity of 161.9 mAh g–1 after 85 cycles. This study provides a reference for solvent selection in the wet processing of sulfide solid-state batteries.