Amorphous nanostructured hydrated electrochemical manganese dioxide (EMD) was potentiodynamically deposited on stainless steel (SS). Electrolyte medium used for the deposition was 0.5 M H2SO4 + 0.5 M MnSO4.5H(2)O. The scan rate of deposition was varied between 50 and 200 mV s(-1). The EMD deposited SS electrodes were characterized by cyclic voltammetry (CV) in 0.1 M Na2SO4 for electrochemical redox supercapacitors. The specific capacitance (SC) of EMD increases by increasing the scan rate of deposition. For EMD deposited at 200 mV s(-1), a maximum SC of 482 F g(-1) was obtained from cyclic voltammetry at a scan rate of 10 mV s(-1). For the same electrode, a SC value of 275 F g(-1) was obtained even at a high scan rate of 150 mV s(-1), indicating high power characteristics of the material. The SC was found to increase with the increase in thickness of EMD. Long cycle-life and stability of EMD were also demonstrated. (C) 2004 Elsevier B.V. All rights reserved.