Ionic liquid modified graphene aerogel as efficient electrode material for supercapacitors based on ionic liquid electrolyte

Abstract

The simultaneous enhancement of energy density (E) and power density (P) is a highly pursued but difficult task in domain of supercapacitors, which necessitates good electrode/electrolyte compatibility, high electron/ion migration rates, and wide voltage window. Herein, an ionic liquid (IL) assisted hydrothermal reduction and modification tactics is employed to prepare 1-benzyl-3-methyl imidazolium cysteine ([Bzmim][Cys]) IL-modified reduced graphene oxide aerogel material (IL-rGA). The porous texture with suitable pore sizes and IL-modified surface of IL-rGA ensures rapid infiltration and sufficient adsorption of electrolyte ions, and therefore substantially enhances the specific capacitance. The symmetric IL-rGA supercapacitor using 1-ethyl-3-methyl tetrafluoroborate IL electrolyte delivers high E values of 104–33 W h kg−1 in the P range of 944–15,860 W kg−1, these output parameters can meet the requirements in more widespread electric facilities. The current work offers a promising way to enhance and balance the E and P values of carbonaceous supercapacitors via the surface modification of electrode materials and the matching with IL electrolytes.