Nanostructured manganese oxide electrodes are electrochemically synthesized by cyclic voltammetric and potentiostatic methods. Electrode structure greatly influences the electrochemical performances of the capacitors. An electrode composed of evenly distributed 30 nm nanorods fabricated by cyclic voltammetry has a higher specific surface area, which possesses a higher capacitance of 243.2 F/g. A specific capacitance of potentiostatic deposited electrode is only 210.4 F/g due to the lower specific area. Pore distribution of a nanostructured electrode was analyzed by ac impedance technique. The potentiostatic deposited electrode has a higher percentage of large pores than the cyclic voltammetric deposited electrode, and therefore is capable of delivering high power. (C) 2004 The Electrochemical Society.