Using a novel graphene/carbon nanotubes composite for enhancement of the supercapacitor electrode capacitance

Graphene and carbon nanotubes have drawn scientific attention as effective nanomaterials for electrical supercapacitors. This study aims to increase the productivity and the performance of eco-friendly supercapacitor electrodes at a low cost. This paper investigates the capacity enhancement of the supercapacitor carbon-based electrodes utilizing varied ratios of graphene and carbon nanotubes. The effects of electrolyte concentrations on supercapacitor electrode electrochemical performance have been studied as well. Using the electrochemical exfoliation, and arc discharge of graphite rods, the graphene, and carbon nanotubes were prepared, respectively. X-ray diffraction, Raman shift spectrum, and high-resolution transmission electron microscopy (HRTEM) have been used to investigate the nanomaterials. The micrographs of the HRTEM indicate that the average tube diameters of the carbon nanotubes are about 179 ± 81 nm. The effective carbon nanocomposite electrodes are analyzed by the traditional electrochemical cyclic voltammetry technique. The highest specific capacitance of graphene/carbon nanotubes composite amounts to about ≈ 179 F/g at a scan rate of about 10 mV/sec for a 3:1 graphene to carbon nanotubes ratio with 1 M NaCl as the electrolyte.