Mechanically and Thermally Robust Gel Polymer Electrolytes with Dynamic Hydrogen-Bond Networks for Wide-Temperature Lithium Metal Batteries

Developing high-energy-density lithium metal batteries (LMBs) demands electrolytes with intrinsic safety and wide-temperature adaptability. However, conventional gel polymer electrolytes (GPEs) face performance limitations at extreme temperatures. Current strategies focus on liquid component optimization but involve complex formulations and fail to meet extreme-environment requirements. This study develops a hydrogen bond-reinforced composite GPE (SA-GPE) by coincorporating Al₂O₃ nanoparticles and SSZ-13 zeolite into the PVDF-HFP matrix, forming a 3D interpenetrating network. The abundant surface hydroxyl groups on SSZ-13 and Al₂O₃ establish a robust multihydrogen-bond network with fluorine atoms (-F) in PVDF-HFP polymer chains. This interaction enhances the mechanical strength and thermal stability and effectively suppresses gel degradation at high temperatures while preventing polymer chain rigidification at low temperatures. Moreover, the hydrogen-bonding network ensures homogeneous filler dispersion, significantly inhibiting particle aggregation during cycling and maintaining structural integrity. Additionally, the filler-polymer interface facilitates rapid Li⁺ transport, and the Lewis acidic sites on Al₂O₃ promote lithium salt dissociation. The microporous structure of SSZ-13 confines PF₆^- mobility, further boosting Li⁺ transference. The SA-GPE demonstrates improved Li⁺ transference number (0.71), high ionic conductivity (2.38 mS/cm) even under -20 °C, and stable Li plating/stripping for 1000 h at 0.5 mA cm^-2. When paired with LiFePO₄, full cells maintain 92% capacity after 1000 cycles at room temperature and deliver excellent performance under extreme conditions (-20 °C-50 °C). This work provides a practical strategy for developing safe, wide-temperature-operable LMBs.