A Highly Adhesive Binder Enables Sulfide‐Based All‐Solid‐State Batteries with High Cycling Stability at Low Stack Pressure

ABSTRACT Sulfide‐based all‐solid‐state lithium‐ion batteries are promising next‐generation energy storage systems owing to their high energy density and enhanced safety. However, the contact loss and unwanted reactions at the electrode|electrolyte interface lead to capacity degradation, which impedes their commercialization. Herein, we introduced hydroxyl polar groups into commercial polystyrene‐ b ‐polybutadiene‐ b ‐polystyrene (SBS) binder via click chemistry. The modified SBS‐Click binder could form hydrogen bonds with the LiNi 0.9 Co 0.06 Mn 0.04 O 2 @Li 3 BO 3 cathode active material and the sulfide electrolyte, thereby enhancing adhesion strength even in non‐polar solvents compared to SBS. Consequently, SBS‐Click cells exhibited superior rate performance and cycling stability over both SBS‐ and HNBR‐based cells, particularly under comparatively lower stack pressure conditions. The cells using SBS‐Click delivered areal capacities of up to 5.4 mAh cm −2 at 0.1 C and at room temperature and 175 MPa. Notably, they achieved about 83% capacity retention after 6000 cycles at 3 C. Furthermore, stable operation exceeding 10 000 cycles was also achieved with 5 C. Overall, this work paves the way for alleviating electro‐chemo‐mechanical failures in all‐solid‐state lithium‐ion batteries, accelerating their commercialization.