Hydrothermal preparation of Co3O4@graphene nanocomposite for supercapacitor with enhanced capacitive performance

Co3O4@graphene nanocomposite (Co3O4@GE) was prepared by a facile hydrothermal route. X-ray diffraction and transmission electron microscope proved CO3O4 nanoparticles with an average size of 5.8 nm were homogeneously dispersed on sonication-exfoliated graphene sheets. X-ray photoelectron spectra indicated a low oxidation degree of graphene in Co3O4@GE. Small amount of functional groups on graphene sheets not only worked as anchor sites for Co3O4 nanoparticles, but also kept the carbon framework with lower defect density. Electrochemical experiments on Co3O4@GE showed high specific capacitance of 415 F/g at a large current density of 3 A/g in 6 M KOH electrolyte, which is valuable for practical application in supercapacitors. (C) 2012 Elsevier B.V. All rights reserved.