Polyaniline (Pani) powder doped with dimethylsulfate (DMS) has been used as an electrode material for all solid-state power source devices such as polymer based lithium secondary battery and redox supercapacitor. The electrochemical properties of Pani powder doped,with DMS (Pani-DMS) have been investigated by using impedance analysis, cyclic voltammetry and charge/discharge measurement. Its specific capacity for lithium secondary battery is similar to100 mA h/g at 1st cycle and similar to85 mA h/g after 100th cycles, and its specific capacitance for redox supercapacitor is similar to130 F/g at 1st cycle and similar to85 F/g after 5000th cycles. (C) 2004 Elsevier B.V. All rights reserved.