The glucose-assisted synthesis of a graphene nanosheet-NiO composite for high-performance supercapacitors

A green and facile approach was used for the synthesis of a graphene nanosheet NiO composite. Using glucose as the green reduction agent, graphene oxide was reduced to graphene and formed a membrane-like NiO-GNS-GC composite via a hydrothermal method. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, the electrochemical performance of the composite was evaluated by cyclic voltammetry and galvanostatic charge-discharge. The obtained NiO-GNS-GC composite exhibits the highest specific supercapacitance of 1495 F g(-1) at a current density of 0.5 A g(-1) in 6 M KOH, which is much higher than that of pure NiO (478 F g(-1)) and pure GNS (92 F g(-1)) along with 90% specific capacitance remaining after 1000 cycles. This could be attributed to the layered sandwich nanostructure and the fact that during the hydrothermal process glucose transformed to a kind of amorphous carbon which, as a spacer, could stabilize the structure of the as-prepared GNS.