Yolk Type Asymmetric Ag–Cu2O Hybrid Nanoparticles on Graphene Substrate as Efficient Electrode Material for Hybrid Supercapacitors

Abstract

Abstract Yolk type asymmetric Ag–Cu2O hybrid nanostructures are in situ synthesized on reduced graphene oxide (RGO) sheets for the first time under one pot hydrothermal mild reaction condition. The co-reduction method provides a facile and straight forward approach to metal/metal oxide hybrid NPs growth on graphene nanosheets and the nano heterostructures are found to be homogeneously distributed over graphene sheets with unique yolk type morphology forming Ag–Cu2O/RGO nanocomposite (NC). The supercapacitor performances of the NCs are evaluated in aqueous 6.0 M KOH by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) in two electrode cell assembly using Ag-Cu2O/RGO as electrode material. The ternary NCs exhibit excellent hybrid capacitance behavior having ~812 Fg−1 specific capacitance value with high energy density 27.2 Wh kg−1 and power density 285 W kg−1, respectively, at current density of 0.5 Ag−1 that suits for potential applications in hybrid capacitor. The high capacitance property of ternary NCs without use of binder can be attributed to excellent electronic/ionic conductivity due to presence of highly conductive graphene sheets in addition of noble Ag metal and unique yolk type morphology which causes faster electronic conduction among different components of the electrode material.