Imidazolium Functionalized\nCopolymer Supported Solvate\nIonic Liquid Based Gel Polymer Electrolyte for Lithium Ion Batteries

Limitations of ionic conductivity and mechanical strength\nrestrict\nthe use of solid electrolytes for lithium ion batteries (LIBs) and\nhence macromolecules, with nonvolatile organic solvents playing a\ncrucial role in stable gel electrolytes. Hence, we have demonstrated\na unique approach to the synthesis of the copolymer-aided solvate\nionic liquid (SIL)-based gel polymer electrolyte, embedded with lithium\nsalt and copolymer, as a viable route for next-generation lithium-ion\nbatteries. A unique and deliberately designed imidazolium-inherited\nbifunctional ionic liquid (B-IL) monomer has been synthesized. Further,\nthe copolymer scaffold is meticulously engineered by varying the composition\nof poly(ethylene glycol) methacrylate (PEGMA) and imidazole-functionalized\nionic liquid (B-IL) monomer. The developed electrolytes accomplished\nan impressive ionic conductivity of 10<sup>–4</sup> S cm<sup>–1</sup> and a compressive elastic modulus of 0.100 MPa at\nroom temperature. An enhanced Li<sup>+</sup> mobility in cooperation\nwith a copolymeric gel electrolyte leads to a lithium transference\nnumber value of 0.71. Moreover, it demonstrates superior stability\nagainst lithium metal, remarkable dendrite suppression, and an admirable\nelectrochemical performance of Li/Gel electrolyte/LiFePO<sub>4</sub> cells. The copolymer networks embedded in nonvolatile solvate ionic\nliquid (SIL)-based electrolytes represent a promising avenue toward\nrealizing highly conductive and mechanically robust gels as electrolytes\nfor stretchable lithium-ion battery (LIB) technology.