부산대학교 도서관

Graphene platelets with a large scale have been synthesized by reduction of graphene oxide (GO)in aqueous solution of hydrazine hydrate under microwave irradiation (MWI). Microstructure ofthe graphene was characterized by X-ray di®raction (XRD), Raman spectroscopy, atomic forcemicroscopy (AFM) and transmission electron microscopy (TEM) together with the selected areaelectron di®raction (SAED). The electrochemical properties were evaluated by the analysis ofcyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1 M Na 2 SO 4aqueous solution. The results show that the as-prepared materials consist of crumpled, few-layer( 3 nm) thick and electronically conductive graphitic sheets. The supercapacitors fabricatedusing this material possess a low equivalent series resistance (ESR) value 1.6 and a highspeci¯c capacitance of 285 F g 1 . In addition, the graphene reduced under a diverse duration ofMWI displays a di®erent interlayer spacing, extent of reduction, level of graphitization andspeci¯c capacitances. The duration of MWI and the treatment methods strongly a®ect the mi-crostructure of graphene, and then dominate its electrochemical properties.