Self-assembled 3D hierarchical nanostructure of reduced GO nanosheets intercalated with CDs for high-rate supercapacitor electrodes

A simple hydrothermal method for the preparation of 3D net-work hierarchical nanostructures consisting of carbon dots (CDs) intercalated between reduced graphene oxide (GO) nanosheets (denoted as CDs@rGONS) is demonstrated in this work. The incorporation of CDs as nano-spacers has effectively preventing aggregations of the rGONS, and at the same time greatly improved the reduction efficiency of the GO, both of which obviously enhance the electrochemical performance of the hierarchical nanostructures. Simple supercapacitors were assembled using the samples with different CDs/GO mass ratios, and it was proved that for the sample obtained with a CDs/GO mass ratio of 0.6 (denoted as CDs@rGONS(0.6)), a high specific capacitance of 239 F/g was obtained according to the CV curves. Moreover, a high energy density of 24 Wh/kg at 1 A/g and a high power density of 15.8 kW/kg at 10 A/g were obtained respectively, both of which are much higher than those without the presence of CDs. The good cycle stability (92.1% capacitance retention after 11500 cycles) of the sample was studied too. These excellent electrochemical performances proved their potential energy storage applications. (C) 2017 Elsevier B.V. All rights reserved.