Superior All‐Solid‐State Batteries Enabled by a Gas‐Phase‐Synthesized Sulfide Electrolyte with Ultrahigh Moisture Stability and Ionic Conductivity

Abstract Sulfide solid electrolytes (SEs) are recognized as one of the most promising candidates for all‐solid‐state batteries (ASSBs), due to their superior ionic conductivity and remarkable ductility. However, poor air stability, complex synthesis process, low yield, and high production cost obstruct the large‐scale application of sulfide SEs. Herein, a one‐step gas‐phase synthesis method for sulfide SEs with oxide raw materials in ambient air, completely getting rid of the glovebox and thus making large‐scale production possible, is reported. By adjusting substituted elements and concentrations, the ionic conductivity of Li 4‐ x Sn 1‐ x M x S 4 can reach 2.45 mS cm −1 , which represents the highest value among all reported moist‐air‐stable and recoverable lithium‐ion sulfide SEs reported. Furthermore, ASSBs with air/water‐exposed and moderate‐temperature‐treated Li 3.875 Sn 0.875 As 0.125 S 4 even maintains superior performances with the highest reversible capacity (188.4 mAh g −1 ) and the longest cycle life (210 cycles), which also breaks the record. Therefore, it may become one of the most critical breakthroughs during the development of sulfide ASSBs toward its practical application and commercialization.