Simple and cost-effective synthesis of activated carbon@few layers of graphene composite electrode for supercapacitor applications

Abstract

We report a simple and low-cost technique to prepare a composite comprising of activated carbon and few layers of graphene sheets and fabricated as electrode material for supercapacitor (SC) applications. The composite is characterised by using Raman spectroscopy, powder X-ray diffraction (XRD), scanning electron microscope (SEM) and current-voltage (I-V) measurements. The synthesized composite is investigated by using galvanostatic chargedischarge (GCD) and cyclic voltammetry (CV) measurements in 3M KOH aqueous electrolyte to evaluate its electrochemical performance. The composite results high specific capacitance from 173 to 564 F/g at different scan rates (100-5 mV/s), analysed by CV and the capacitances resulted in GCD measurement were 196 to 587 F/g at various current densities (5-1 A/g). The cycle stability of the as-prepared AC/graphene composite is also tested and observed that 89% of capacitance is retained even after 5000 cycles which reveals the excellent long term chargedischarge stability of the prepared composite. Therefore, the composite performs very well in storage as well as life cycling. The obtained results suggest that AC/graphene composite can be a suitable electrode material for high-performance SC.