Interfacial self-healing engineered bifunctional quasi-solid electrolyte for high-performance lithium-sulfur...

Given their low cost and high energy density, lithium‑sulfur batteries (LSBs) are an appealing alternative for next-generation battery systems. However, the shuttle effect of polysulfides and the growth of lithium dendrites during battery operation severely hinder the practical application of LSBs. Here, we propose an interfacial self-healing strategy to prepare the bifunctional Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)/Graphene oxide (GO)/Copper benzene-1,3,5-tricarboxylate (HKUST-1)/Borate bond Quasi-Solid-State Electrolyte (PHGKB QSSE), which significantly improves the electrochemical performance of LSBs. The synergistic interaction between borate bonds and graphene oxide significantly enhances the interaction between HKUST-1 and PVDF-HFP, which not only enhances the mechanical properties and ability to eliminate lithium dendrites of the QSSE, but also effectively anchors polysulfides to suppress the shuttle effects and forms rapid Li⁺ transport channels. The PHGKB QSSE shows outstanding elongation at break (312 %), high areal capacity (3.65 mAh cm^-2), excellent thermal stability (200 °C), and high-capacity retention (with a capacity decay rate of 0.052 % per cycle over 500 cycles), which is superior to that of previously reported quasi-solid polymer electrolytes. Density functional theory calculations elucidated the mechanism by which interface self-healing strategies enhance the anchoring of polysulfides and lithium ion transport kinetics. This study developed an innovative interfacial self-healing strategy based on molecular-level design for high-performance quasi-solid-state LSBs.