Synthesis of Colloidal Graphene by Electrochemical Exfoliation of Graphite in Lithium Sulphate

Abstract

We report the synthesis of colloidal graphene via electrochemical exfoliation of graphite in Li2SO4 aqueous solution. In this electrochemical exfoliation method, high quality graphene was prepared within short time of 1.5 hr. This electrochemical exfoliation mechanism suggests that SO42- and H2O are intercalated into graphite sheets and as a result single and few-layer graphene sheets are produced with SO2 and O2 gases. The electrochemically exfoliated colloidal graphene was stable in NMP solvent for more than 2 weeks. The colloidal graphene was used for preparing the conducting graphene electrodes by brush painting on A4 paper for flexible supercapacitor applications. Our method exhibits potential for large-scale synthesis of good-quality graphene and its applications in flexible energy storage devices such as supercapacitors.