Reduced graphene oxide based ternary nanocomposite cathodes for high-performance aqueous asymmetric supercapacitors

Abstract

Ternary nanocomposites have attracted increasing attention as efficient supercapacitor electrode materials. Here we report, the synthesis of a ternary hybrid nanocomposite by the introduction of crystalline RuO2 nanoparticles loaded carbon nanocoils (CNCs) as spacers in reduced graphene oxide (RGO). The RGO-(RuO2/CNCs) composite electrode exhibits a high specific capacitance of 725Fg−1 at a scan rate of 20mVs−1 in three-electrode configuration. When used in symmetric two electrode configuration, it shows a specific capacitance of 436Fg−1 at a constant current density of 1Ag−1, which is nearly three times higher than that of pure RGO based electrode. An aqueous asymmetric supercapacitor fabricated using RGO-(RuO2/CNCs) as the positive electrode and RGO as the negative electrode is operational in an electrochemically stable potential window of 2V. The asymmetric capacitor exhibits a high energy density of 45WhKg−1 at a power density of 1kWkg−1 and retains an energy density of 41WhKg−1 even at a high power density of 40kWkg−1.