Imidazolium Functionalized Copolymer Supported Solvate Ionic Liquid Based Gel Polymer Electrolyte for Lithium Ion Batteries

Limitations of ionic conductivity and mechanical strength restrict the use of solid electrolytes for lithium ion batteries (LIBs) and hence macromolecules, with nonvolatile organic solvents playing a crucial role in stable gel electrolytes. Hence, we have demonstrated a unique approach to the synthesis of the copolymer-aided solvate ionic liquid (SIL)-based gel polymer electrolyte, embedded with lithium salt and copolymer, as a viable route for next-generation lithium-ion batteries. A unique and deliberately designed imidazolium-inherited bifunctional ionic liquid (B-IL) monomer has been synthesized. Further, the copolymer scaffold is meticulously engineered by varying the composition of poly(ethylene glycol) methacrylate (PEGMA) and imidazole-functionalized ionic liquid (B-IL) monomer. The developed electrolytes accomplished an impressive ionic conductivity of 10–4 S cm–1 and a compressive elastic modulus of 0.100 MPa at room temperature. An enhanced Li+ mobility in cooperation with a copolymeric gel electrolyte leads to a lithium transference number value of 0.71. Moreover, it demonstrates superior stability against lithium metal, remarkable dendrite suppression, and an admirable electrochemical performance of Li/Gel electrolyte/LiFePO4 cells. The copolymer networks embedded in nonvolatile solvate ionic liquid (SIL)-based electrolytes represent a promising avenue toward realizing highly conductive and mechanically robust gels as electrolytes for stretchable lithium-ion battery (LIB) technology.