Feasible study of polypyrrole film in single and double cationic ionic liquids as novel electrolytes for energy storage applications

- The single and double cationic ionic liquids were synthesized.
- The single and double cationic ILs were used as an electrolyte for pTS doped PPy supercapacitor electrode.
- The capacitive performance was increased with decreasing chain length of ILs, for both single and double cation ILs.

We report the supercapacitive performance of p-toluene sulfonic acid (pTS) doped polypyrrole (PPy) thin film tested in series of ionic liquid (IL) salt electrolytes based on single and double imidazolium IL. The IL salt electrolytes were prepared by dissolving 0.1 M of the total salt concentration in deionized water and their ionic conductivity was measured. The electrochemical properties of pTS doped PPy film as an active material in single and double cationic IL electrolytes were evaluated using cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy analysis. It is observed that the effects of the number of cation in IL salts are significant in determining their potential applications for supercapacitors. The results showed that the pTS doped PPy film in double cationic IL electrolytes exhibited higher specific capacitance value than that of single cationic IL electrolytes. Among double cationic IL electrolyte, C4(MIm)2(BF4)2 was most promising candidate for supercapacitor because of their higher specific capacitance value (222 Fg−1) and enhanced rate capability induced due to lower solution resistance of the electrolyte.