‘Graphene-MnO2’ Composite Supercapacitor Material accomplished tactically by using Liquid-Liquid and Solid-Liquid Interface Reaction Techniques.
A novel methodology is described to grow architecture of 3-dimensional graphene nanosheets (GNS)-manganese oxide (MnO2) composite material to be used in supercapacitors. In situ growth of the three dimensional MnO2 fiber-network over the surface of graphene layers is achieved at the solid-liquid interface. The composite electrode shows good electron and charge transfer, rapid plus reversible Faradic reaction and excellent cyclic ability in electrochemical studies. Electrochemical properties of the prepared GNS-MnO2/FTO electrode material are assessed by cyclic voltammetry and galvanostatic charge/discharge tests. The specific capacitance of the GNS-MnO2 reaches 683 Fg-1 at a current density of 2.2 Ag-1 and shows excellent cycle stability retaining 96.9 % of initial capacitance up to 5000 cycles. A coulomb efficiency of about 99 % displayed by GNS-MnO2/FTO electrode is an excellent recital for desired supercapacitor material. Herein, the charge storage mechanism in 3-dimensional graphene nanosheets (GNS)-manganese oxide (MnO2) composite is discussed in detail. Furthermore, at an elevated current density of ~10.86 Ag-1, the power density is achieved to be ~6.235 kWkg-1, maintaining energy density of ~7.99 kWhkg-1; thus demonstrating promising and potential of electrode material for supercapacitor application.