Abstract:

A novel MnO2/MSAC(micro-spherical activated carbon base on mesocarbon microbead) composite, which might be used as an electrode material in electrochemical capacitor, was prepared by dispersing thermally decomposed MnO2 from manganese nitrates on MSAC. The morphology and crystal structure of the composite were investigated by scanning electron microscopy(SEM)， transmission electron microscope(TEM) and X-ray diffraction(XRD), respectively. The electrochemical properties of the electrode were studied by cyclic voltammetry(CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy(EIS) in 1.0 mol/L LiPF6. Our results showed that the MnO2 particles dispersed on MSAC have particle size in the range of 100~160 nm, the initial specific capacitance of the MSAC/MnO2 and single MSAC electrode are 186 F/g and 167 F/g respectively at 2×10-3 A/cm2 current density. The Coulombic efficiency of MnO2/MSAC spherical compound materials capacitor remained above 95% after 200 charge and discharge cycles. In addition, the charge-discharge curve of the MSAC/MnO2 electrode showed typical capacitive behavior with a good linearity, and the CV curve also showed good rectangular features, high energy density and good power performance.

Key words: Electrochemical capacitor, Manganese oxide, MCMB, Composite electrode