###### Abstract  
Gel electrolytes (GEs) play a pivotal role in the advancement of lithium metal batteries by offering high energy density and enhanced rate capability. Nevertheless, their real-world application is hampered by relatively low ionic conductivity and significant interfacial resistance at room temperatures. In this work, we developed a gel electrolyte membrane (GEM) by embedding Zeolitic Imidazolate Framework-8 (ZIF-8) metal-organic frameworks (MOFs) material into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix through UV curing. The composite membrane, with 4 wt% ZIF-8, exhibited an ionic conductivity of 1.17 \(\times\) 10\({}^{-3}\) S/cm, an electrochemical stability window of 4.7 V, and a lithium-ion transference number of 0.7. The test results indicate that the electrochemical performance of LFP//GEM//Li battery has an initial specific capacity of 168 mAh g\({}^{-1}\) at 0.1 C rate. At 1 C, the discharge capacity was 88 mAh g\({}^{-1}\), and at 2 C, it was 68 mAh g\({}^{-1}\). Enhanced ionic transport, improved electrochemical stability, and optimized lithium-ion migration collectively contributed to superior rate performance and prolonged cycle life. This study offers novel insights and methodological advances for next-generation lithium metal batteries technologies. gel electrolyte; Metal-Organic Frameworks; PVDF-HFP; UV curing technology; lithium metal batteries +
Footnote †: journal: ApJ  
0000-0001-9001-9001-9001-9001-9001-9001-9001-9001-9011-9001-901-9001-9001-901-901-901-9001-901-901-9001-9001-901-901-9001-901-901-9001-901-9001-9001-9001-901-901-9001-901-9001-9001-901-9001-901-9001-9001-901-9001 molecular weight materials, have been widely employed in the early development of gel electrolyte membranes due to their highly stable chemical properties and outstanding mechanical durability [11; 12]. In recent years, researchers have synthesized PVDF-HFP copolymers by copolymerizing vinylidene fluoride (PVDF) with hexafluoropropylene (HFP) [13], which increased the proportion of amorphous regions in the copolymer, markedly enhancing ion transport properties [14; 15]. [PERSON] et al. further improved the system by incorporating garnet-type Li\(\gamma\)La\({}_{3}\)Zr\({}_{2}\)O\({}_{12}\) (LLZO) nanoparticles into the PVDF-HFP matrix. The plasticizing effect of LLZO particles endowed the composite with excellent electrochemical performance and cycling stability [16]. [PERSON] et al. fabricated porous polyethylene separators coated with a PVDF-HFP/PMMA composite via a simple dipping process under 40% relative humidity, achieving a maximum ionic conductivity of 1.69 mS/cm [17]. Metal-organic frameworks (MOFs) are a class of porous materials with tunable pore sizes and exceptionally high specific surface areas, offering a novel approach to the design of lithium metal batteries [18; 19]. These materials feature well-ordered channel structures and high porosity [20], which provide continuous pathways and abundant active sites for ion transport. Moreover, the organic ligands and metal nodes in MOFs can be flexibly modified through chemical functionalization to optimize their electrochemical performance [21]. The high thermal stability of MOFs [22], along with their composite structures with polymers, enhances the mechanical strength of electrolytes, suppresses lithium dendrite growth, and accommodates volume changes during charge-discharge cycles [23]. [PERSON] et al. constructed a three-dimensional MOF crosslinked network asymmetric solid polymer electrolyte (SPE) via in situ polymerization. By selectively sieving anions through the MOF layers, the lithium-ion transference number was elevated to 0.72. The nanostructured MOF layers serve as a shield, effectively suppressing Li dendrite growth and ensuring uniform Li\({}^{+}\) transport [24]. [PERSON] et al. proposed a novel design for a polyethylene oxide (PEO)-based SPE by incorporating activated Copper 1,3,5-phenyltricarboxylic acid (HKUST-1) MOFs into the PEO electrolyte.