Graphene quantum dots-induced morphological changes in CuCo2S4 nanocomposites for supercapacitor electrodes with enhanced performance

Graphene quantum dots (GQDs) have been explored in recent years for electrochemical applications with considerable potentials. Here, we present GQD-doped CuCo2S4 nanocomposites through two-step hydrothermal process for supercapacitor electrodes. The surface of CuCo2S4 nanosheets changes from smooth to particles-accumulative shape, which assists the electrochemical cycling processes as well as the ion diffusion and charge transfer kinetics for improved supercapacitor performances. As a result, GQD/CuCo2S4 electrodes demonstrate a specific capacitance of 1725 F g−1 under a current density of 0.5 A g−1 and a cycling life of 10,000 cycles by retaining 90% of the energy storage capability. As such, this work extends the potential of GQDs in electrochemical applications by means of morphology change of CuCo2S4 nanosheets.