High-performing, flame-resistant gel polymer electrolytes derived from PMMA side chain grafted P(VDF-HFP) based nanocomposite membranes for lithium-ion batteries

We report on high-performance gel polymer electrolytes (GPEs) with outstanding physical, electrical, electrochemical, and fire-resistant characteristics. Highly porous copolymer membranes are developed by grafting PMMA side chains onto the P(VDF-HFP) copolymer backbone, followed by blending with variable percentages of imidazolium ionic liquid (IL) functionalized SiO₂ nanoparticles. Finally, the GPEs are obtained by submerging the porous membrane in an organic electrolyte solution. The GPE exhibits outstanding ion conductivity of 6.09 mS cm^–1 with an appreciable lithium ion transference number (0.57) at room temperature and excellent compatibility with Li electrodes. The Li/LiFePO₄ cell comprising the optimized GPE delivers a high reversible capacity of ∼132 mAh g⁻¹ at 2C and high discharge capacities of 155.9 and 141.2 mAh g⁻¹ after consecutive 40 and 60 cycles at C/3 and 1C rates, respectively. With its improved electrochemical performances and high level of safety, the as-developed GPE has a lot of promise for use in LMBs.