Preparation and supercapacitive performance of nanosized manganese dioxide/ordered mesoporous carbon composites

The MnO2/ordered mesoporous carbon composites (MnO2/OMCs) with nanosized MnO2 embedded in ordered mesoporous carbons are prepared by the redox reaction of KMnO4 with ordered mesoporous carbon CMK-8 synthesized by KIT-6 as the hard template. The structure and morphology of the as-prepared MnO2/OMCs are characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherm, Fourier infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results reveal that different MnO2 contents are successfully introduced into the pores of CMK-8, and the obtained MnO2/OMCs can still maintain the ordered mesostructure and large specific surface area. The electrochemical properties of all the MnO2/OMCs samples are studied by cyclic voltammetry (CV), galvanostatic charge/discharge tests, electrochemical impedance spectroscopy (EIS) and cycle life measurements in 6 mol L−1 KOH electrolyte. Due to the combination of the electrical double layer capacitance of CMK-8 and the redox pseudocapacitance of MnO2, the specific capacitance of the MnO2/OMC electrodes increases with the increase of the MnO2 contents, and a maximum specific capacitance of 576.10 F g−1 at the scan rate of 1 mV s−1 can be achieved for MnO2/OMC-0.04.