We demonstrate the efficient doping of reduced graphene oxide (RGO) by Chlorine and its capacitive performance was calculated by cyclic voltammetry and charge-discharge cycling in 1 M H2SO4 solution. In this regard, we are prepared RGO nanosheets through a simple, eco-friendly and efficient electrochemical method, with selectively functionalized edges by chlorine which involves added the RGO to the halogen containing acid solution and dispersed by ultrasonic. After synthesis, Cl-RGO is characterized using X-ray diffraction, Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, Energy-dispersive X-ray (EDX) spectroscopy and tunneling electron microscopy. FTIR spectra show the chlorine-containing functional groups. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of doped chlorine in RGO. Raman spectroscopy shows a high density of defects in the RGO layer. Electrochemical characteristics of Cl-RGO are characterized by cyclic voltammetery, galvanostatic charge/discharge and electrochemical impedance spectroscopy. According to the galvanostatic charge/discharge analysis, Cl-RGO represents specific capacitance (Cs) of 178.4 F g(-1) at current density of 1 A g(-1), which is higher than that of RGO (100.5 F g(-1)) in H2SO4 solution. (C) 2016 Elsevier Inc. All rights reserved.