Hydrous manganese oxide was deposited on graphite substrates at anodic potentials of 0.5-0.95 V versus saturated calomel electrode (SCE) in 0.25 M Mn(CH3COO)(2) solution at 25 degrees C. Morphology of manganese oxide prepared was examined by scanning electron microscopy (SEM). Manganese oxide deposited at various anodic potentials was evaluated by cyclic voltammetry with various potential scan rates in different electrolytes. Results indicated that the pseudocapacitive behaviors of manganese oxide were excellent both in 2M KCl and 2M (NH4)(2)SO4 solutions at room temperature. Manganese oxide deposited at 0.5 V versus SCE showed better capacitive behaviors, the specific capacitances were 275 F/g in 2 M KCl solution and 310 F/g in 2 M (NH4)(2)SO4 solution, respectively. Besides, better electrochemical reversibility could be obtained in 2 M KCl solution. (c) 2006 Elsevier Ltd. All rights reserved.