1D/2D Co3O4/Graphene Composite Electrodes for High-Performance Supercapacitor Applications

摘要

Nanostructured Co3O4/reduced graphene oxide (rGO) composite material has been synthesized by a hydrothermal method. Urea was used as a structure-directing and assembling agent for Co3O4 nanorods. The structure and morphology of the as-synthesized Co3O4/rGO composite were investigated by x-ray diffraction analysis, scanning electron microscopy, and high-resolution transmission electron microscopy. Fourier-transform infrared spectroscopy analysis confirmed successful reduction of rGO and formation of the composite. Qualitative Raman spectral analysis of GO and the Co3O4/rGO composite revealed the reestablishment of an sp(2)-conjugated network of carbon atoms after reduction of graphene. Electrochemical analysis disclosed the pseudocapacitive behavior of the composite electrode material. The specific capacitance of the composite electrode was calculated to reach a higher value of 916.6 F g(-1) at 0.5 A g(-1) in 1 M KOH electrolyte, with excellent rate capability and long-term stability including 98% capacitance retention after 1000 cycles. This outstanding capacitive performance makes the Co3O4/rGO hybrid nanocomposite a promising candidate for use in supercapacitors.