CuMn2O4 spinel anchored on graphene nanosheets as a novel electrode material for supercapacitor

•CuMn2O4-RGO was first prepared by sol-gel method and then synthesized by physical grinding.•The capacitance of CuMn2O4-RGO (1:1) reached 342 F g−1 at the current density of 1.0 A g−1.•CuMn2O4-RGO (1:1) has excellent energy density and power density.•CuMn2O4-RGO (1:1) exhibited better cyclic stability than pure RGO and CuMn2O4. Copper manganese oxide-graphene (CuMn2O4-RGO) composite was prepared by sol-gel method and then synthesized by physical grinding, which was further applied to electrode materials for supercapacitors. The structure and morphology of the composites were analyzed by means of characterization, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), transmission electron microscopic (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, and Raman. The electrochemical tests including cyclic voltammetry (CV), galvanostatic charge-discharge, electrochemical impedance spectroscopy (EIS) and cyclic life were used to investigate electrochemical properties of CuMn2O4-RGO so as to optimize its composition. Through the comparison of electrochemical properties at different mass ratios, current densities and scan rates, it was found that when the mass ratio was m (CuMn2O4): m (RGO) =1:1, the as-prepared CuMn2O4-RGO exhibited the excellent electrochemical properties. The capacitance reached 342 F g−1 at the current density of 1.0 A g−1, which was significantly higher than that of pure CuMn2O4 and RGO. The higher capacitance performance can be comparable with the reported literature value. Meanwhile, the energy density of CuMn2O4-RGO (1:1) is significantly higher than that of CuMn2O4 and RGO. Therefore, CuMn2O4-RGO (1:1) composite has a good prospect as electrode material for supercapacitor. [Display omitted]