Manipulating conditions of electrochemical exfoliation of graphite for high-quality graphene has become a research hotspot in recent years. In this study, based on controlled electrochemical exfoliation of graphite in aqueous ammonium sulfate electrolyte to produce graphene, a green, economic, and facile one-step method was developed to synthesize sulfur particles supported on the surface of graphene (SPG). Thiourea (CH4N2S), acted as sulfur source, and regulated radicals (e.g., HO center dot), thus controlling the exfoliation, and subsequently resulting in formation of sulfur particles supported on SPG. During electrochemical exfoliation at room temperature, electrochemical performance of the as-prepared SPG (1% CH4N2S) electrode exhibited a high specific capacitance of 186.3 F g(-1) at a scan rate of 1 mV s(-1) compared with that of the graphene (112.1 F g(-1), 1 mV s(-1)) without added thiourea. Temperature of electrochemical exfoliation was reduced to investigate of regulation of radicals and thus to control exfoliation. Electrochemical performance of the graphene prepared by reducing electrode temperature exhibited a high specific capacitance of 174.2 F g(-1) at a scan rate of 1 mV s(-1), when temperature of electrochemical exfoliation was reduced to 15 degrees C. (c) 2017 Published by Elsevier Ltd.