Nitrogen and sulfur Co-Doped graphene quantum dots decorated CeO2 nanoparticles/ polyaniline: As high efficient hybrid supercapacitor electrode materials

Abstract Recently, hybrid supercapacitor due to high energy/power density and long cycle life has been attractive field for energy researchers. In this work, we demonstrated the decoration of graphene quantum dots on metal oxide/polyaniline to form efficient electrode materials for a hybrid supercapacitor for the first time. Ultrafine N and S co-doped graphene quantum dots (N,S-GQDs) were grown on CeO 2 nanoparticles via in situ hydrothermal method. Then, PANI-N,S-GQDs@CeO 2 nanocomposites have been prepared by the chemical oxidation polymerization process. The simultaneous incorporation of S and N species in GQDs provides a larger active surface and greatly increases the contact area with the CeO 2 in polymer nanocomposite. The as prepared material was analyzed by spectroscopic techniques and electron microscopy analysis. Electrochemical properties of the PANI-N,S-GQDs@CeO 2 as supercapacitor electrodes were investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy experiments. The maximum specific capacity of 189 C g −1 was obtained for PANI/5 wt % N,S-GQDs@CeO 2 nanocomposite at current density of 1 A g −1 in comparison with 175 and 115 C g −1 for PANI/10 wt% N,S-GQDs@CeO 2 and PANI/5 wt% CeO 2 respectively. Value of specific capacity remained at 75% after 1000 cycles under the current density of 1 A g −1 .