Self-Healable and Superrobust Supramolecular Elastomer-Bound Sulfide Electrolyte Films for Dendrite-Free...

The commercialization of all-solid-state lithium batteries (ASSLBs) is hindered by the lack of advanced binders for sulfide solid-state electrolyte (SSE) films, as current binders often fail to achieve cohesion and adhesion balance, resulting in agglomeration or insufficient mechanical strength. Herein, we introduce a self-healable supramolecular poly-(urethane-urea) (SPU) binder for sulfide SSE films, leveraging dynamic hydrogen bonds to achieve a balance between adhesion and cohesion. The SPU binder enables the fabrication of free-standing Li₆PS₅Cl (LPSCl) films at a low binder content of 3 wt %, achieving an ionic conductivity of 1.5 mS cm^-1 and a highly densified morphology. The resulting lithium symmetric cell exhibits a critical current density (CCD) of 1.8 mA cm^-2 and cycling stability over 3500 h at 0.1 mA cm^-2, and lithium dendrite growth is revealed to be largely mitigated in the LPSCl film. Furthermore, ASSLBs incorporating SPU-bound LPSCl films demonstrate enhanced rate capability (140.6 mAh g^-1 at 1C) and cycling performance (78.8% capacity retention after 400 cycles). This work highlights the potential of self-healable binders in addressing the mechanical and electrochemical challenges of sulfide SSE films, paving the way for scalable ASSLB development.