Investigation of electrochemical reduction effects on graphene oxide powders for high-performance supercapacitors

This study aims to investigate the electrochemical reduction effects on graphene oxide (GO) powders with various bias voltages and treatment times. Phosphate-buffered saline solution was used as the electrolyte in the electrochemical reduction process. The experimental results showed that the GO powders were reduced to produce the best reduced GO (rGO) powders as using a bias of −17.5 V for 2 h. After the analysis of Raman spectra for GO and rGO powders, the intensity ratios of the D and G bands increased from 0.85 to 1.08, respectively. The carbon to oxygen ratios increased from 0.4 to 1.79 measured by an X-ray photoelectron spectroscopy. Moreover, the electrical conductivity obviously increased from 7.92 × 10⁻⁴ to 4.16 × 10⁻¹ S/cm. Fourier transform infrared spectra revealed the disappearance of oxygen-containing functional groups in rGO powders. According to the cyclic voltammetry analysis, the specific capacitance of the rGO powders could reach 183 F/g at the scan rate of 100 mV/S in 1 M KCl electrolyte solution. This specific capacitance value was 16 times higher than that obtained with the GO powders. The results indicated that the produced high-quality rGO powders could be used for high-performance supercapacitors.