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

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 Li6PS5Cl (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 Li6PS5Cl-MgF2 electrolyte therefore presents a high critical current density (2.3 times that of pristine electrolyte). The LiCoO2/Li6PS5Cl-MgF2/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.