Mn3O4/reduced graphene oxide nanocomposite electrodes with tailored morphology for high power supercapacitor applications

Abstract

A nanocomposite of manganese oxide (Mn3O4) and reduced graphene oxide (rGO) is obtained by simple, physical mixing of the components and its suitability as electrode material for high power supercapacitors is analysed by detailed electrochemical characterization. Mn3O4 nanorods of average diameter 36nm is synthesized via hydrothermal method and rGO, by chemical reduction of GO, obtained by modified Hummer’s method. The structural and morphological studies using XRD, Raman spectroscopy, BET, SEM and TEM techniques reveal that, in the nanocomposite, the Mn3O4 nanorods are dispersed homogenously within the rGO layers, with the structural characteristics of the component materials kept intact. The nanocomposite electrode with the component materials taken in 1:1 ratio shows excellent 3 electrode electrochemical performance in 1M Na2SO4 and 2 electrode performance in organic electrolyte. The 3 electrode measurements show specific capacitance of 228Fg−1 at 5Ag−1 for the nanocomposite electrode. The 2 electrode measurements using symmetric supercapacitor test cells give a capacitance of 94Fg−1, an energy density of 82 Wh kg−1 at 1Ag−1, a power density of 7097Wkg−1 and good cycling stability with 95% of the initial capacitance remaining after 5000 cycles at 5Ag−1.