Asymmetric Functional Gel Polymer Electrolyte Enables Superior Interfacial Compatibility for Wide Temperature Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) represent a promising candidate for next-generation energy storage systems, yet their practical application is constrained by limited cycle life owing to slow interface Li+ ion transport and severe interfacial side reactions, particularly in extreme temperature conditions. Herein, a novel asymmetric gel polymer electrolyte (GPE) is constructed through sequential electrospinning and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) filler integration to achieve high compatibility with Li anode and high-voltage cathode over wide temperature range. The polyethylene oxide (PEO)/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix adjacent to the Li anode homogenizes Li⁺ ion flux and facilitates the formation of stable solid electrolyte interphase (SEI) through dynamic interfacial remodeling. At the cathode side, the polyacrylonitrile (PAN)/PVDF-HFP matrix exhibits outstanding high-voltage tolerance, effectively suppressing transition metal dissolution and electrolyte decomposition. The incorporated LLZTO enhances LiPF6 dissociation via selective adsorption. The highly porous asymmetric polymer framework architecture facilitates the elimination of macroscopic interfaces among dissimilar materials, achieving fast Li⁺ ion transport. Consequently, the Li||Ni0.8Co0.1Mn0.1O2 cells exhibit outstanding wide temperature cycling of -30 to 70 °C. This asymmetric structure design of GPE offers valuable insights into interfacial engineering exploration for all-climate LMBs.