Preparation of colloidal graphene in quantity by electrochemical exfoliation

We reported the preparation of colloidal graphene in quantity via the anodic exfoliation of graphite in (NH4)(2)SO4 aqueous solution. In the currently designed electrochemical exfoliation route, mass highquality graphene was produced within short reaction time, around 1 h. The proposed electrochemical exfoliation mechanism showed that SO42- and H2O can be intercalated into those graphite sheets, monolayer and few-layer graphene were obtained by the formation of gaseous SO2 and O-2 within graphite sheets. Stability evaluation showed that our exfoliated colloidal graphene can be perfectly stabilized in DMF solvent more than I week. The colloidal graphene can be used to construct various simple and complex patterns by writing it on A4 paper, which can be applied to flexible printed electronic devices. Furthermore, colloidal graphene can show promising applications in the fabrication of binder- and additive-free electrodes for supercapacitors and lithium-ion batteries. Our present method shows huge potential for industrial-scale synthesis of high-quality graphene and further commercialization of graphene colloid for numerous advanced applications in flexible printed electronics and energy storage devices. (C) 2014 Elsevier Inc. All rights reserved