Spherical Mn3O4 nanoparticles were synthesized by microwave assisted reflux method at different reaction times (1, 5, 10, 15, and 20 min). The single phase formation of Mn3O4 nanoparticles was identified through XRD analysis. The FT-IR and Raman spectra revealed the presence of functional groups of Mn3O4 and further support the XRD results. The spherical morphology of Mn3O4 was identified via SEM analysis. The cyclic voltammetry analysis implies that 15 min synthesized Mn3O4 (MN-15) shows the higher specific capacitance of 135 F g(-1) among all the prepared Mn3O4 electrodes. The EIS spectra of MN-15 substantiate the less charge-transfer resistance (R-ct) of 0.553 Omega, when compared with the other samples. The discharge capacitance of MN-15 was 103 F g(-1) at 0.5 mA cm(-2) in 1 M NaNO3 solution. The cycling stability curve over 100 cycles implies that the discharge capacitance is increased from 47 to 68 F g(-1) at 5 mA cm(-1). This capacitance enhancement during cycling is due to the influence of phase or morphological variation of Mn3O4 electrodes. (C) 2012 Elsevier B. V. All rights reserved.