title: Organic Radical-Assisted Electrochemical Exfoliation for the Scalable Production of High-Quality Graphene.
abstract: Despite the intensive research efforts devoted to graphene fabrication over the past decade, the production of high-quality graphene on a large scale, at an affordable cost, and in a reproducible manner still represents a great challenge. Here, we report a novel method based on the controlled electrochemical exfoliation of graphite in aqueous ammonium sulfate electrolyte to produce graphene in large quantities and with outstanding quality. Because the radicals (e.g., HO(•)) generated from water electrolysis are responsible for defect formation on graphene during electrochemical exfoliation, a series of reducing agents as additives (e.g., (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), ascorbic acid, and sodium borohydride) have been investigated to eliminate these radicals and thus control the exfoliation process. Remarkably, TEMPO-assisted exfoliation results in large graphene sheets (5-10 μm on average), which exhibit outstanding hole mobilities (∼405 cm(2) V(-1) s(-1)), very low Raman I(D)/I(G) ratios (below 0.1), and extremely high carbon to oxygen (C/O) ratios (∼25.3). Moreover, the graphene ink prepared in dimethylformamide can exhibit concentrations as high as 6 mg mL(-1), thus qualifying this material for intriguing applications such as transparent conductive films and flexible supercapacitors. In general, this robust method for electrochemical exfoliation of graphite offers great promise for the preparation of graphene that can be utilized in industrial applications to create integrated nanocomposites, conductive or mechanical additives, as well as energy storage and conversion devices.
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Brüller
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Zhong-Shuai
authors.initials: ZS
authors.lastname: Wu
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Khaled
authors.initials: K
authors.lastname: Parvez
authors.affiliation: Center for Advancing Electronics Dresden (CFAED) and Department of Chemistry and Food Chemistry, Technische Universität Dresden , Mommsenstraße 4, 01062 Dresden, Germany.
authors.forename: Renhao
authors.initials: R
authors.lastname: Dong
authors.affiliation: ISIS, Université de Strasbourg , 8 Allée Gaspard Monge, 67083 Strasbourg, France.|icFRC, CNRS , 8 Allée Gaspard Monge, 67083 Strasbourg, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Richard
authors.affiliation: ISIS, Université de Strasbourg , 8 Allée Gaspard Monge, 67083 Strasbourg, France.|icFRC, CNRS , 8 Allée Gaspard Monge, 67083 Strasbourg, France.
authors.forename: Paolo
authors.initials: P
authors.lastname: Samorì
authors.affiliation: Center for Advancing Electronics Dresden (CFAED) and Department of Chemistry and Food Chemistry, Technische Universität Dresden , Mommsenstraße 4, 01062 Dresden, Germany.
authors.forename: Xinliang
authors.initials: X
authors.lastname: Feng
authors.affiliation: Max-Planck-Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen