Investigation of the effect of different ionic liquids on the capacitive performance of biomass derived activated carbon

Abstract

Stable ionic liquids (ILs) are promising materials for extending the potential applications of electrolytes. Herein, the effects and capacitance performance of various ILs consisting of the same 1-butyl-3-methylimidazolium ([bmim]) cation and three different anions: bromide (Br-), chloride( Cl-), and hexafluorophosphate (PF6-) have been investigated with activated carbon (AC) derived from banana leaves for supercapacitor (SCs) applications. The specific capacitance (Csp) values were obtained 177, 318, and 280 F g-1 in [bmim]Br, [bmim]Cl, [bmim]PF6 electrolytes, respectively. The effect of the size of anions and polarizability has been found to affect the capacitance performance. In [bmim]Cl, the AC has obtained the best capacitance performance and rate capability. A comparison of electrochemical performance revealed that the electrolyte anions have a significant effect on the SCs efficiency. A mini-prototype device has been prepared to demonstrate the practicality of the AC and [bmim]Cl electrolytes. This study is expected to broaden the applications of ILs for SC devices.