Sonochemical synthesis of porous nanowall Co3O4/nitrogen-doped reduced graphene oxide as an efficient electrode material for supercapacitors

A composite of nitrogen-doped reduced graphene oxide (NRGO) with nano-sized Co3O4 was prepared using a sonochemical method. The prepared Co3O4/NRGO samples were assessed through field emission scanning electron microscopy, X-ray diffraction, X-ray photoemission spectroscopy, and Raman spectroscopy to obtain chemical, structural and morphological information. The resulting composite (Co3O4/NRGO) was evaluated as a candidate for building supercapacitor electrodes. In this line the electrochemical performance of the tested materials were studied through cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy, and continues cyclic voltammetry. The electrochemical tests were performed using 3 M KCl solutions as the electrolyte. The evaluations on Co3O4/NRGO-based electrodes revealed the material to have a specific capacitance (SC) of 763 F g(-1) at a scan rate of 2 mV s(-1), an energy density (ED) of 138 W h kg(-1), and a high rate capability. Continues cyclic voltammetry evaluations using Co3O4/NRGO-based electrodes proved the electrodes to be capable of maintaining almost 98.9% of its initial SC after 4000 cycles. Based on the electrochemical evaluations the synthesized nanocomposite was proven to possess the merits of both of its ingredients.