In this paper, MnO2 center dot xH(2)O/carbon aerogel (CRF) composite electrode materials were prepared by a chemical co-precipitation method. The structure and morphology of MnO2 center dot xH(2)O/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 MnO2 center dot xH(2)O powders possessed, a nanoscaled structure, and thus the MnO2 center dot xH(2)O/CR-F 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 MnO2 center dot xH(2)O/CRF composite electrodes had good electrochemical performance, high reversibility and high charge-discharge properties. Moreover, when the loading amount of MnO2 center dot xH(2)O was 60%, the composite material has a high specific capacitance of 226.3 F g(-1), while the capacitance of carbon aerogel electrode alone was 112F g(-1). Besides, MnO2 center dot xH(2)O/CRF composite supercapacitors showed a stable cycle life in the potential range of 0-1.0 V and retained 90% of initial capacitance over 400 cycles. (c) 2006 Elsevier B.V. All rights reserved.