A new type of MnO_2 centre dot xH_2O/CRF composite electrode for supercapacitors

摘要

In this paper, MnO_2 centre dot xH_2O/carbon aerogel (CRF) composite electrode materials were prepared by a chemical co-precipitation method. The structure and morphology of MnO_2 centre dot xH_2O/CRF were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that carbon aerogel was an amorphous material with a pearly network structure, the MnO_2 centre dot xH_2O powders possessed, a nanoscaled structure, and thus the MnO_2 centre dot xH_2O/CRF composite materials were nano-sized particles with a relatively high specific surface area. Electrochemical performance of the composite electrodes with different ratio's was studied by cyclic voltammetry and galvanostatic charge/discharge measurements. The results indicated that MnO_2 centre dot xH_2O/CRF composite electrodes had good electrochemical performance, high reversibility and high charge-discharge properties. Moreover, when the loading amount of MnO_2 centre dot xH_2O was 60 percent, the composite material has a high specific capacitance of 226.3 Fg~(-1), while the capacitance of carbon aerogel electrode alone was 112 Fg~(-1). Besides, MnO_2 centre dot xH_2O/CRF composite supercapacitors showed a stable cycle life in the potential range of 0-1.0 V and retained 90 percent of initial capacitance over 400 cycles.