Preparation of MnO2/graphene nanocomposite for the application of supercapacitor

Graphene oxide was synthesized by an improved method, and then MnO₂/graphene oxide composite was obtained using chemical precipitation. The MnO₂/graphene nanocomposite was obtained via hydrazine reduction of the MnO₂/graphene oxide composite. The morphology and surface chemical composition of the composites have been investigated by scanning electron microscope (SEM), Fourier transform infrared spectrum (FT-IR) and X-ray diffraction (XRD), respectively. The capacitive properties of the MnO₂/graphene nanocomposite were measured using cyclic voltammetry and galvanostatic charge/discharge tests and electrochemical impedance spectroscopy in a double-electrode experimental setup using a 1 mol/L Na₂SO₄ aqueous solution as the electrolyte. The results of galvanostatic charge/discharge show that the composite has good electrochemical performance and the average capacitance is as high as 188.69 F/g at 1 A/g in the 1 mol/L Na₂SO₄ solution aqueous electrolyte.