The manganese oxides and polyaniline composite thin film was chemically deposited on porous carbon electrode through oxidizing aniline thin film by a KMnO4 solution. The capacitance and stability of this composite film were investigated by cyclic voltammetry (CV). The redox properties of the MnO2-polyaniline (M-P) thin film exhibited ideal capacitive behavior in a 0.1 M Na2SO4 solution. The capacitance of M-P film materials can reach 500 F g(-1) and maintains about 60% of the initial capacitance after 5000 cycles. The structure and surface morphology of M-P film were examined in terms of the X-ray diffraction patterns (XRD) and scanning electron microscopic (SEM) photographs. The composition of M-P film was also studied by X-ray photoelectrons (XPS). (c) 2005 Elsevier B.V. All rights reserved.