An effective route to produce few-layer graphene using combinatorial ball milling and strong aqueous exfoliants

Abstract

In this paper, a simple, cost effective, and scalable process for production of fewlayer graphene is reported by combining ball milling with exfoliants. The graphene was derived from low-cost graphite, which was subjected to high-energy ball milling in an aqueous medium containing a strong exfoliant (1-pyrenecarboxylic acid) and a common solvent methanol. Such a combinatorial approach has not been used before. At a fixed concentration of 1-pyrenecarboxylic acid, the extent of exfoliation was found to be strongly dependent upon the energy input from the ball milling process (expressed as number of hours of milling) and the solvent used. The graphene produced had the distinctive Raman signature, x-ray diffraction crystallinity, scanning electron microscopic image features, transmission electron microscopic images, and high conductivity values (6.7 Â 10 3 S m À1 ) in 4-probe electrical measurements all of which compared reasonably with typical values achieved for few-layer graphene. Application of the few-layer graphene was investigated as an electrode for supercapacitors. The graphene-coated electrode showed good specific capacitance and area capacitance ($176 F g À1 and 1.6 F cm À2 ), superior to conventionally processed graphene. Also demonstrated is good stability in multiple cyclic voltammetric cycles as also a low fade in capacitance after 100 cycles. Based on the obtained characteristics, which show high degree of fidelity when compared to commercial graphene, the few-layer graphene was considered to be a good cost-effective and scalable alternative for applications in energy and other fields. V C 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4809794] 033123-2 Aparna et al. J. Renewable Sustainable Energy 5, 033123 (2013) 033123-5 Aparna et al. J. Renewable Sustainable Energy 5, 033123 (2013) 033123-8 Aparna et al.

Quantitative evaluation of delamination of graphite by wet media milling

“…These methods inherit the combination of functionalization and delamination of graphite [43][44][45][46]. A drawback for planetary ball milling techniques is the long process time (about 24 h) [43][44][45] and/or requirement of ultrasound-assisted post-dispersing steps [41,42,46]. Usually, high energy ball milling favors in-plane fracture in comparison with delamination which limits the yield and leads to defective sheets.…”

“…Dry milling of graphite in an SO 3 atmosphere and in presence of dry ice yields graphene functionalized with carboxylic and sulfonic acid groups [44,45]. These methods inherit the combination of functionalization and delamination of graphite [43][44][45][46]. A drawback for planetary ball milling techniques is the long process time (about 24 h) [43][44][45] and/or requirement of ultrasound-assisted post-dispersing steps [41,42,46].…”

“…Recently, planetary ball milling techniques of graphite in wet or dry state have been developed continuously for graphene production [38][39][40][41][42][43][44][45][46]. Dry milling of graphite in an SO 3 atmosphere and in presence of dry ice yields graphene functionalized with carboxylic and sulfonic acid groups [44,45].…”

Mechanochemical Route to Functionalized Graphene and Carbon Nanofillers for Graphene/SBR Nanocomposites

“…Therefore, several approaches have been made to exploit mechanical delamination and solvent‐mediated exfoliation of graphite for tailoring graphene and graphene‐like carbon nanomaterials as cost‐effective carbon nanofillers. On the one hand, wet grinding of graphite in the presence of solvents, such as ethanol and N , N ‐dimethylformamide, and surfactants, such as 1‐pyrene carboxylic acid, sodium dodecyl sulfate, or polystyrene, affords graphene dispersions. However, most dispersions have rather low concentrations well below 1 wt.‐% graphene.…”

Scalable production of wrinkled and few-layered graphene sheets and their use for oil and organic solvent absorption

“…Han et al reported that monolayer graphene can be obtained through a mechanical exfoliation method. [15][16][17][18][19][20] Thus, the development of new facile and solid-phase approaches for high-yield production of high quality graphene is highly desired. 12 Recently, liquid-phase exfoliation of natural graphite has opened up a simple way to prepare graphene simply using sonication of graphite powders in various solvents (such as N-methylpyrrolidone and 1,2-dichlorobenzene) or surfactants solutions.…”