Polar anchoring effect-mediated solvation regulation in fluorinated gel polymer electrolytes for high-voltage...

High-voltage lithium-ion batteries (LIBs) demand both high energy density and intrinsic safety, yet conventional phosphate-based electrolytes suffer from catastrophic co-intercalation with graphite anodes. Herein, we report a flame-retardant fluorinated gel polymer electrolyte (TFF-PH) engineered via a polar anchoring effect to overcome this incompatibility. By in situ polymerizing hexafluorobutyl acrylate (HFBA) and pentaerythritol tetraacrylate (PETEA), the resulting framework utilizes polar polymer chains to anchor phosphate molecules through strong dipole-dipole interactions. This mechanism reconstructs the Li⁺ solvation structure by reducing the participation of phosphate molecules in the primary Li⁺ solvation shell and restricting solvent mobility to suppress co-intercalation while promoting a robust, inorganic-rich SEI. Furthermore, HFBA-derived fluorine radicals effectively scavenge combustion-sustaining species, ensuring superior flame retardancy. Consequently, MCMB‖NCM811 full cells using TFF-PH exhibit exceptional stability, retaining 80% capacity after 200 cycles at 4.4 V and showing high durability at 4.5 V. With a high ionic conductivity of 6.09 mS cm^-1 and a Li⁺ transference number of 0.655, this anchoring strategy provides a transformative pathway for safe, high-voltage battery systems.