Organic‐Additive‐Derived Cathode Electrolyte Interphase Layer Mitigating Intertwined Chemical and Mechanical Degradation for Sulfide‐Based Solid‐State Batteries

Keeping both the chemical and physical state of electrode–electrolyte interface intact is one greatest challenges in achieving solid-state batteries (SSBs) with longer cycle lives. Herein, use organic electrolyte additives cathode interphase (CEI) layer to mitigate intertwined mechanical degradation sulfide-based SSBs demonstrated. Lithium difluorobis(oxalato)phosphate (LiDFBOP) argyrodite (Li6PS5Cl) are used as a model system, LiDFBOP-derived CEI induced by irreversible oxidation above 4.12 V (vs Li+/Li) during formation exhibiting dual functions. This retards rate between active particles solid electrolytes at high charging potential helps maintain intimate contact even low stack pressure 0.75 MPa. The improved enables delivery initial capacity, while stability suppressing sulfite or sulfate has more dominant effect on long-term stability. study presents new perspective strategies for designing coating materials beyond typically inorganic oxide materials.