Solvent-engineered synthesis of sulfide solid electrolytes for high performance all-solid-state batteries

All-solid-state lithium batteries (ASSLBs) fabricated with solid electrolytes (SEs) have attracted significant interest due to their advantageous properties like excellent safety, durability, and energy density. Among all SEs, argyrodites, such as Li6PS5Cl (referred to as LPSCl), are regarded as promising candidates for ASSLBs. However, the conventional ball-milling preparation method is not ideal for scale-up, while solution-based manufacturing methods suffer from poor ionic conductivity. Herein, we report lithium phosphorus sulfide chloride (LPSCl) superionic SEs prepared from a liquid-phase, scalable method. The developed approach facilitates the preparation of highly soluble precursors using common polar solvents. We found that the purity of LPSCl SEs was dependent on the solvent properties, with the appropriate solvents in solution-based manufacturing methods to produce SEs with a high ionic conductivity (maximum 2.20 mS cm−1) and miniscule electron conductivity. Electrochemical evaluation of a cell with the as-prepared SEs was successfully demonstrated in ASSLBs.