High-yield scalable graphene nanosheet production from compressed graphite using electrochemical exfoliation

Abstract

Electrochemical exfoliation is a promising bulk method for producing graphene from graphite; in this method, an applied voltage drives ionic species to intercalate into graphite where they form gaseous species that expand and exfoliate individual graphene sheets. However, a number of obstacles have prevented this approach from becoming a feasible production route; the disintegration of the graphite electrode as the method progresses is the chief difficulty. Here we show that if graphite powders are contained and compressed within a permeable and expandable containment system, the graphite powders can be continuously intercalated, expanded, and exfoliated to produce graphene. Our data indicate both high yield (65%) and extraordinarily large lateral size (>30 μm) in the as-produced graphene. We also show that this process is scalable and that graphene yield efficiency depends solely on reactor geometry, graphite compression, and electrolyte transport.

Molecular Design of Core Substituted Naphthalene Diimides for the Exfoliation of Graphite to Graphene in Chloroform

“…From Figure , the wide scan survey spectra of all samples show a dominant peak at 283.9 eV of C1s suggestive of high quality material with minimal oxidation . The samples also show a high carbon/oxygen (C/O) ratio ranging from 15.9–25.7 comparable to that of the starting material graphite (Figure S2) further showing that our exfoliation process introduces minimal oxygenation unlike the case of graphene oxide where C/O ratios as low as 4.98 have previously been reported . Also notable is the absence N1s peak at 400 eV in all films indicative of the absence of residual cNDI following washing of films further showing non‐covalent interactions of cNDI and exfoliated graphite.…”

“…Prominent D bands are due to the breathing mode of the sp 2 carbon atoms and are usually exacerbated by the presence of defects such as basal plane or new edges formed especially during sonication, functional groups/dopants and structural disorders . The G band is attributed to first‐order scattering of the E 2g mode of sp 2 hybridized carbon bonds and the spectral shape of the 2D band provides information on the graphene layer number for graphene flakes . From Figure , for graphite exfoliated in cNDI‐chloroform, we observe relatively stronger D band intensities compared to films from graphite exfoliated in cNDI‐NMP, which has been reported to be the result of flake edges acting as defects during Raman scattering .…”

“…Figure shows the normalized spectra with typical graphene vibrational bands: the D band (1350 cm −1 ) and G band (1600 cm −1 ), as well as 2D band (2700 cm −1 ). Prominent D bands are due to the breathing mode of the sp 2 carbon atoms and are usually exacerbated by the presence of defects such as basal plane or new edges formed especially during sonication, functional groups/dopants and structural disorders . The G band is attributed to first‐order scattering of the E 2g mode of sp 2 hybridized carbon bonds and the spectral shape of the 2D band provides information on the graphene layer number for graphene flakes .…”

Two‐Dimensional Electrocatalysts for Efficient Reduction of Carbon Dioxide

“…denotes the counter electrode, which, for example, can be either platinum or another graphite rod. Reproduced with permission . Copyright 2018, Nature Publishing Group.…”

Anomalous Discharge Behavior of Graphite Nanosheet Electrodes in Lithium-Oxygen Batteries

“…The graphite expansion has not exclusively negative consequences, because GNS are theoretically capable of reaching a multiple of the discharge capacity they would reach, if only their outer particle surface provides space for discharge products. The electrochemically induced expansion and exfoliation of graphite could be exploited as a facile and inexpensive way to unlock the full discharge capability of graphite [56,57,[61][62][63]. Presumably, the anomalous discharge behavior of GNS has implications for the deep discharge of any graphite-or multilayer graphene-based cathode, or even electrodes that employ other two-dimensional layered materials.…”