Molecular Engineering of Fluorinated Hybrid Gel Polymer Electrolytes Enables Ultra‐Wide‐Temperature Operation of High‐Voltage Lithium Metal Batteries

ABSTRACT The development of wide‐temperature gel polymer electrolytes (GPEs) represents a promising strategy for enhancing the extreme environment tolerance of lithium‐metal batteries (LMBs), which requires simultaneously optimizing Li + transport kinetics at low temperatures and maintaining the thermal and mechanical stability. This work addresses the intrinsic limitations of conventional GPEs by employing a molecular engineering strategy that achieves molecular‐scale hybridization of organic and inorganic units. Specifically, a fluorinated hybrid gel polymer electrolyte (FHPE) is fabricated through the in situ crosslinking polymerization of trifluoroethyl acrylate (TFEA) and acryloxypropyl polyhedral oligomeric silsesquioxane (Acry‐POSS) within 2,2‐difluoroethyl acetate (DFEA). The FHPE displays high Li + conductivity (3.54 × 10 −4 S cm −1 at −30°C), broad electrochemical stability window (>4.7 V), and remarkable mechanical strength (58.7 MPa). Moreover, the FHPE promotes the formation of LiF‐rich interphases on the LiCoO 2 cathode and lithium metal anode, thereby effectively mitigating dendrite growth and interfacial side reactions. Consequently, FHPE‐based Li/Li coin cells stably cycle for 1500 h at 0.3 mA cm −2 and −30°C, while Li/LiCoO 2 coin cells exhibit 86.7% capacity retention after 200 cycles at −30°C and 77.9% after 400 cycles at 60°C. Furthermore, Li/FHPE/LiCoO 2 pouch cells exhibit stable operation during nail penetration tests, thereby confirming their exceptional safety.