Insight of super-capacitive properties of flexible gel polymer electrolyte containing butyl imidazole ionic liquids with different anions based on PVDF-HFP

Supercapacitors based on ionic liquid gel polymer electrolytes (GPEs) have attracted considerable attention as a new energy storage device due to their good specific capacitance, good cycling capacity and stability. In this work, flexible gel polymer electrolyte (GPE) films were prepared and applied using three butyl imidazole ionic liquids with different anions as additives based on polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The structure and the mechanical properties of the GPE films and the electrical properties of the assembled symmetrical supercapacitors have been characterized. In particular, the structure–activity relationship between the structure and properties of the gel electrolyte was revealed by combining calculations with experiments. In particular, the structure–activity relationship between the structure and properties of the GPE was revealed through the combination of calculation and experiment. The results show that the electronegativity of the anions plays an important role in improving the stability and electrochemical properties of the gel system. This work is useful to further verify the influence of the anionic component of ionic liquids on the physical and chemical properties of gel electrolytes and to prepare more excellent solid electrolytes for supercapacitors.