Synergic Exfoliation of Graphene with Organic Molecules and Inorganic Ions for the Electrochemical Production of Flexible Electrodes

Abstract

A facile and efficient method based on electrochemistry for the production of graphene‐based materials for electronics is demonstrated. Uncharged acetonitrile molecules are intercalated in graphite by electrochemical treatment, owing to the synergic action of perchlorate ions dissolved in acetonitrile. Then, acetonitrile molecules are decomposed with microwave irradiation, which causes gas production and rapid graphite exfoliation, with an increase in the graphite volume of up to 600 %. Upon further processing and purification, highly dispersible nanosheets are obtained that can be processed into thin layers by roll‐to‐roll transfer or into thicker electrodes with excellent capacitance stability upon extensive charging/discharging cycles. The good exfoliation yield (>50 % of monolayers), minimal oxidation damage and good electrochemical stability of the nanosheets obtained were confirmed by scanning force and electron microscopy, as well as Raman spectroscopy and galvanostatic analyses.

New‐Generation Graphene from Electrochemical Approaches: Production and Applications

“…Notably, 69% of the graphene fl akes were bilayers and 28% of them were single layers with mean lateral dimensions of 1-2 µm. [ 36 ] Ionic liquids (ILs) have been proposed as the alternatives to conventional organic electrolytes. Previous studies have revealed that a small amount of water in imidazolium-based ionic liquids is crucial for effi cient exfoliation.…”

“…As an alternative to these approaches pristine graphene has been used to create 3D porous structures such as aerogels [ 48 ] and foams. [ 36,49 ] Furthermore, electrochemical exfoliation has been facilitated as a surface treatment for graphitic fi brous networks and graphite foils; here the EEG sheets are only partially exfoliated whereas the graphene source itself remains structurally intact, providing support for the exfoliated material. [ 27,50 ] Another promising fi eld is the use of graphene as an anode material in lithium ion batteries.…”

Graphene-based coatings on polymer films for gas barrier applications

“…In this approach, an electrochemical setup is used to expand bulk graphite into highly soluble EGO sheets in few minutes, thanks to the synergic gas evolution from the decomposition of intercalated electrolytes and graphite oxidation [23,24]. EGO can be rapidly obtained with a high yield, unlike the conventional GO or the graphene exfoliated by sonication in organic solvents.…”

Nanoscale Mechanics of Graphene and Graphene Oxide in Composites: A Scientific and Technological Perspective

“…Such approaches have obtained a high degree of exfoliation of graphite in few minutes by using electrolyte solutions less troublesome than the strong acids required for GO production via the Hummers' method. [32,33] A main advantage of electrochemical exfoliation is that it allows to fine-tune the sheet oxidation, giving sheets that are larger and more soluble than those obtained by ultrasound exfoliation, but have less defects than the GO sheets produced by the Hummers' method. (For a systematic comparison of sonication, chemical and electrochemical exfoliation techniques see ref.…”