Local Charge Distribution Regulation toward Sulfide Superionic Conductor for Superior Electrochemical Performance in All-Solid-State Batteries

Sulfide-based all-solid-state batteries are currently a focal point of research for next-generation energy storage solutions. However, the poor antioxidative stability of sulfide electrolytes limits their practical applications. In this study, we strengthen sulfur-related bonding interactions by regulating the local charge density of the surrounding sulfur atoms, thereby enhancing the oxidative stability of sulfide electrolytes. First-principles calculations and experimental results demonstrate that substituting certain sulfur in Li9.9SnP2S11.9Br0.1 with oxygen leads to an increase in the local electronic density around unsubstituted sulfur atoms and a reduction in cation–anion bond lengths, which subsequently strengthens the bonds including P–S and Sn–S. Remarkably, the tailored electrolyte also exhibits significant improvements in air stability and chemical compatibility with halide electrolytes. Batteries constructed with the obtained Li9.9SnP2S10.9Br0.1O1.0 electrolyte demonstrated greatly enhanced electrochemical performance. Our results highlight how local charge distribution regulation enhances the chemical and electrochemical stability of sulfide electrolytes, offering valuable insights for creating high-performance all-solid-state batteries.