Graphene and Nanostructured Mn3O4 Composites for Supercapacitors

Mn3O4 nanoparticles and graphene/Mn3O4 composites were synthesized by a facile method. The Mn3O4 nanoparticles were uniformly distributed on graphene nanosheets, which were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The capacitive properties of the Mn3O4, graphene and graphene/Mn3O4 composites have been investigated by galvanostatic charge/discharge, cyclic voltammetry (CV) and electrochemical impendence spectroscopy (EIS). The specific capacitance of Mn3O4 reached 190 F/g at a scan rate of 10mV/s in 5M KOH electrolyte., owing to pseudocapacitance. The G/Mn3O4 nanocomposites achieved a specific capacitance of 140 F/g (27.6% increases than that of graphene), a good rate property and good cycle stability, making them a promising electrode material as supercapacitors.