Hydrogen-Bond and Solvation-Shell Dual Modulation Enables Safe Gel Polymer Electrolyte for Lithium Metal Batteries

Lithium metal batteries promise ultrahigh energy density but suffer from interfacial instability, dendrite growth, and safety risks. Gel polymer electrolytes are a promising solution, but conventional designs suffer from poor interfacial compatibility and lithium dendrite growth. Here, we design an in situ formed nonflammable gel polymer electrolyte (NGPE) that integrates two molecular-level strategies: hydrogen-bond anchoring and solvation-shell regulation. Hydrogen bonds among TMP, PVDF-HFP, and TFSI⁻ immobilize anions, enhancing ionic conductivity and Li⁺ transference. Fluoroethylene carbonate reshapes Li⁺ solvation, leading to the formation of inorganic-rich interphases that suppress dendrites and stabilize interfaces. The optimized NGPE achieves stable Li||Li cycling for over 2800 h and Li||LFP full cells with 74.3% capacity retention after 1000 cycles at 2 C. Pouch cells further demonstrate mechanical robustness and exceptional safety under flame tests. This dual molecular strategy provides a general design principle for safe, dendrite-free quasi-solid-state lithium metal batteries.