One-pot electrodeposition synthesis of ZnO/graphene composite and its use as binder-free electrode for supercapacitor

A simple one-pot green electrodeposition route is presented for the synthesis of ZnO/graphene nanosheets composite. During a electrochemical deposition process, the graphene oxide nanosheets loose oxygen-containing functional group to become graphene nanosheets (GNS), and zinc oxide (ZnO) is also electrochemically deposited on the electrode. Such hybrid microstructure facilitates the charge and ion transport in the electrode, which has been observed by scanning electron microscopy. Besides, the as-prepared ZnO/GNS sample also has been characterized with X-ray powder diffraction and Raman spectra. Moreover, the electrochemical performance of the obtained composite used as supercapacitor electrode is investigated by cyclic voltammerty, galvanostatic charge/discharge, and electrochemical impedance spectra tests. At the current density of 3 Ag−1, the resulting ZnO/GNS composite exhibits an enhanced specific capacitance of 291 Fg−1, much larger than that of pure ZnO (118.8 Fg−1).