Towards scale‐up of graphene production via nonoxidizing liquid exfoliation methods

Abstract

Graphene, the two-dimensional form of carbon, has received a great deal of attention across academia and industry due to its extraordinary electrical, mechanical, thermal, chemical, and optical properties. In view of the potential impact of graphene on numerous and diverse applications in electronics, novel materials, energy, transport, and healthcare, large-scale graphene production is a challenge that must be addressed. In the past decade, top-down production has demonstrated high potential for scale-up. This review features the recent progress made in top-down production methods that have been proposed for the manufacturing of graphene-based products. Fabrication methods such as liquidphase mechanical, chemical and electrochemical exfoliation of graphite are outlined, with a particular focus on nonoxidizing routes for graphene production. Analysis of exfoliation mechanisms, solvent considerations, key advantages and issues, and important production characteristics including production rate and yield, where applicable, are outlined. Future challenges and opportunities in graphene production are also highlighted. V C 2018 American Institute of Chemical Engineers AIChE J, 00: 000-000, 2018 a) Scanning Electron Microscopy (SEM) image of expanded highly orientated pyrolytic graphite from Cooper et al. (b-c) TEM images of mono-and multilayer graphene from Qian et al. d) SEM image of GO from Voiry et al. e) High resolution TEM (HRTEM) image of single layer reduced graphene oxide with indications of holes (red arrow) and oxygen functional groups (blue arrow) from Voiry et al. Reproduced with permission from Ref. 15-17.

Influence of Substrate in Roll-to-roll Coated Nanographite Electrodes for Metal-free Supercapacitors

“…Due to the high electric conductivity and large surface area of nanographites, such as graphene and graphite nanoplatlets, these materials have gained a large interest for use in energy storage devices and printed electronics [1][2][3][4] . Nanographites can be produced by a large variety och routes, but for large-scale production liquid exfoliation techniques seem to be the most promising methods [5][6][7][8][9] . To promote low-cost, sustainable and environmentally friendly devices, water-based solvents is preferred in the process 7,9,10 together with bio-based binders, such as cellulose, instead of polytetrafluoroethylene (PTFE) and polyvinyl alcohol (PVA) 3,4,[11][12][13][14] .…”

Buckling, crumpling, and tumbling of semiflexible sheets in simple shear flow

“…However, there is still much to be learned about the dynamics of sheets subjected to fluid flow. Such fundamental understanding is particularly relevant now, as solution processing and liquid exfoliation [33][34][35][36] are commonly employed techniques in handling 2D materials, and nanosheet mechanical properties can be tuned by altering exfoliation protocols (e.g., solvent properties, the use of surfactant, etc.) 36,37 .…”

Real-time monitoring and hydrodynamic scaling of shear exfoliated graphene

“…The highest performance solvents for liquid exfoliation and dispersion are generally toxic (e.g. NMP), with high boiling points also limiting practical uses [15]. Previous research on carbon nanotubes and graphene have guided solvent and aqueous-surfactant strategies and relied on concentration measurements to assess performance and suitability [35,36].…”

“…Hydrodynamics are central in many nanomaterial exfoliation and dispersion processes that rely on shear-assistance [13][14][15]. Methods have been designed to exceed a minimum shear rate necessary to exfoliate layered materials [14,16] using laminar [17], turbulent [18][19][20][21] and multiphase flows [13] in the search for higher yields and one-pass ink formulation.…”