Organic Molecule-Functionalized Reduced Graphene Oxide for All-Carbon Asymmetric Supercapacitor Applications

An organic molecular electrode (OME) is obtained, in which the polyhydric organic molecules (3,4,5-trihydroxybenzamide, THBA) act as a guest molecule to decorate graphene hydrogel (rGO1). The THBA acts as a spacer to prevent the rGO sheet from aggregation and provides an active center for OME. In the three-electrode configuration, the prepared OME (rGO1-THBA) presents a capacitance of 390.6 F g–1 and has a capacitance retention of 73.7% even when the scanning rate increases from 5 to 100 mV s–1. Furthermore, we synthesize an organic molecule 1,4,5,8-naphthalenetetracarboxylic diimide (NDP) and immobilize it onto the rGO surface to form another OME (rGO-NDP) as the counter electrode. An all-carbon asymmetric supercapacitor (rGO1-THBA//rGO-NDP: ASC) is constructed by using rGO1-THBA and rGO-NDP as the positive and negative electrodes, respectively. The resultant device achieves a capacitance of 70.8 F g–1 and delivers an energy density of 14 W h kg–1, supplying the power of 590 W kg–1. More importantly, the two asymmetric devices in series connection are able to light up 24 LED lights for 100 s.