Preparation of MnO2/WMNT composite and MnO2/AB composite by redox deposition method and its comparative study as supercapacitive materials

The manganese oxide/multi-walled carbon nanotube (MnO2/MWNT) composite and the manganese oxide/acetylene black (MnO2/AB) composite were prepared by translating potassium permanganate into MnO2 which formed the above composite with residual carbon material using the redox deposition method and carbon as a reducer. The products were characterized by X-ray diffraction, Fourier transform infrared, and scanning electron microscope. Electrochemical properties of both the MnO2/MWNT and MnO2/AB electrodes were studied by using cyclic voltammetry, electrochemical impedance measurement, and galvanostatic charge/discharge tests. The results show that the MnO2/MWNT electrode has better electrochemical capacitance performance than the MnO2/AB electrode. The charge-discharge test showed the specific capacitance of 182.3 F center dot g(-1) for the MnO2/MWNT electrode, and the specific capacitance of 127.2 F center dot g(-1) for the MnO2/AB electrode had obtained, within potential range of 0-1 V at a charge/discharge current density of 200 mA center dot g(-1) in 0.5 mol center dot L-1 potassium sulfate electrolyte solution in the first cycle. The specific capacitance of both the MnO2/MWNT and MnO2/AB electrodes were 141.2 F center dot g(-1) and 78.5 F center dot g(-1) after 1,200 cycles, respectively. The MnO2/MWNT electrode has better cycling performance. The effect of different morphologies was investigated for both MnO2/MWNT and MnO2/AB composites.