Electron Redistribution Enables Redox‐Resistible Li6PS5Cl towards High‐Performance All‐Solid‐State Lithium Batteries

Abstract Sulfide electrolytes with high ionic conductivity hold great promise for all‐solid‐state lithium batteries. However, the parasitic redox reactions between sulfide electrolyte and Li metal result in interfacial instability and rapid decline of the battery performance. Herein, a redox‐resistible Li 6 PS 5 Cl (LPSC) electrolyte is created by regulating the electron distribution in LPSC with Mg and F incorporation. The introduction of Mg triggers the electron agglomeration around S atom, inhibiting the electron acceptance from Li, and F generates the self‐limiting interface, which hinders the redox reactions between LPSC and Li metal. This redox‐resistible Li 6 PS 5 Cl‐MgF 2 electrolyte therefore presents a high critical current density (2.3 times that of pristine electrolyte). The LiCoO 2 /Li 6 PS 5 Cl‐MgF 2 /Li cell shows an outstanding cycling stability (93.3 %@100 cycles at 0.2 C). This study highlights the electronic structure modulation to address redox issues on sulfide‐based lithium batteries.