In this study, graphene nanosheets (GNS) were modified by 1-Butyl-3-methylimidazolium hexafluorophosphate, which is one of Ionic Liquid (IL). Owing to the modification of graphene with ionic liquids, graphene can not only be structurally stabilized, but also showed the higher charge transfer that is favor to exhibit an enhanced electrochemical performance. Also, a graphene aggregation by the intersheet van der Waals interaction can be prevented because ionic liquids act as an effective agent for the exfoliation of graphene sheets. The structural analysis of prepared composites was confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and X-ray diffractometer (XRD). The electrochemical properties are studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The GNS/IL composites show a high specific capacitance (114 Fg(-1)) compared to pristine graphene (99 Fg(-1)) at 10 mVs(-1) in 6 M KOH electrolyte. Also, the prepared composites showed the enhanced electrochemical performance such as high rate capability and excellent cycle performance. Therefore, the prepared composites could be a candidate of electrode materials for supercapacitors. (C) 2013 Elsevier Ltd. All rights reserved.