Size selection of dispersed, exfoliated graphene flakes by controlled centrifugation

Khan, Umar; O’Neill, Arlene; Porwal, Harshit; May, Peter; Nawaz, Khalid; Coleman, Jonathan N.

doi:10.1016/j.carbon.2011.09.001

Cited by 276 publications

(263 citation statements)

References 48 publications

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“…4. This value is among the highest reported graphene concentrations for a liquid exfoliation process that was obtained in only after 10 h of sonication which is very short time compared to tens and even hundreds of hours reported previously [21,22,32]. Moreover, the yield and concentration of graphene can further be improved by increasing time of sonication and recycling of sediment.…”

Section: Exfoliation Of Graphite To Graphenementioning

confidence: 47%

“…Irreversible exfoliation of graphite occurs when the surface energy of the solvent is close to the surface energy of graphite which overcomes Van der Waals forces between graphene sheets [14,20]. Among the best tested solvents are 1-methyl-2-pyrrolidinone (NMP) [20][21][22] and halogenated aromatic solvents [23,24]. Even though NMP is widely used in the preparation of electrodes for Li-ion batteries which makes it a natural choice, its toxicity and environmental hazard prompted research toward its replacement with environmentally friendly solvents [25,26].…”

Section: Introductionmentioning

confidence: 99%

“…If graphene containing ethylcellulose solution was dried, the final graphene content in polymer composite would be less than 1.2 wt% which is extremely low taking into account that the binder content in electrode formulations usually does not exceed 5-10 wt% and amount of active material should be maximized (∼90 wt%). Another drawback of sonication assisted liquid exfoliation of graphite is time consuming: hundreds of hours of sonication are required to get reasonable graphene concentration [21,22,32] which impedes using this method for scalable graphene composite production.…”

Section: Introductionmentioning

confidence: 99%

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Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

Naboka

Yim

Abu-Lebdeh

2016

Materials Science and Engineering: B

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1016/j.mseb.2016.04.003Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation Naboka, Olga; Yim, Chae-Ho; Abu-Lebdeh, Yaser http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=53b49153-7e23-4e60-9847-41177eef882f http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=53b49153-7e23-4e60-9847-41177eef882f In the present work, we report a sonication-assisted exfoliation method of graphene preparation enhanced by the use of microwave heating and "green" exfoliant -sodium carboxymethyl cellulose (NaCMC). Introducing microwave heating during sonication of graphite dispersions in aqueous solutions of NaCMC results in the formation of graphene dispersions with concentration as high as 4.29 mg/ml. It is found that drying the dispersions results in the formation of graphene/NaCMC composites with graphene content up to 38.65 wt%. A study of the composite with High Resolution Transmission Electron Microscopy and Raman Spectroscopy reveals the formation of few-layer graphene approximately below five layers. The as-prepared graphene/NaCMC composite shows higher capacities than commercial graphite in Li-ion half cells reaching 397 mAh/g (graphene) . Also, when the composite is used with a nanosilicon (33 wt%) in a Li-ion half cell high initial reversible capacities of 1611 mAh/g (Si) with good cyclability and rate capability have been reached.

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Section: Exfoliation Of Graphite To Graphenementioning

confidence: 47%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

Naboka

Yim

Abu-Lebdeh

2016

Materials Science and Engineering: B

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“…The sonication tends to break up the graphite crystallites as well as exfoliating them to give large number of graphene nanosheets. 11 Raman spectroscopy 15,24,25 shows this method to produce negligible quantities of basal plane defects while XPS shows the akes to be un-oxidised. 14 While the graphene produced by this method is of high quality, some major problems remain.…”

mentioning

confidence: 99%

Turbulence-assisted shear exfoliation of graphene using household detergent and a kitchen blender

et al. 2014

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To facilitate progression from the lab to commercial applications, it will be necessary to develop simple, scalable methods to produce high quality graphene. Here we demonstrate the production of large quantities of defect-free graphene using a kitchen blender and household detergent. We have characterised the scaling of both graphene concentration and production rate with the mixing parameters: mixing time, initial graphite concentration, rotor speed and liquid volume. We find the production rate to be invariant with mixing time and to increase strongly with mixing volume, results which are important for scale-up. Even in this simple system, concentrations of up to 1 mg ml À1 and graphene masses of >500 mg can be achieved after a few hours mixing. The maximum production rate was $0.15 g h À1 , much higher than for standard sonication-based exfoliation methods. We demonstrate that graphene production occurs because the mean turbulent shear rate in the blender exceeds the critical shear rate for exfoliation.Over the last decade, graphene has become one of the most studied of all nano-materials due to its 2-dimensional structure and its unique set of physical properties. 1,2 During this period, the focus of much of the research community has been on mapping out and understanding the fundamental physics and chemistry of graphene. However, in recent years, the emphasis has started to shi slightly towards the demonstration of applications. 3 Over the next few years, we expect the emphasis to shi further as both academic and industrial researchers concentrate on fullling the applications potential of graphene, eventually leading to a range of graphene-enabled products.However, before this can be achieved, it will be critically important to develop industrially scalable production methods for graphene. While graphene can be produced by a range of techniques, many applications will require solution-processed 4 graphene. In particular, a number of applications will require access to large volumes of graphene dispersions or inks. Using standard solution deposition techniques such as inkjet printing 5,6 or spray coating, 7,8 such inks can be used to prepare a range of lms, coatings or patterned structures. In particular, applications in areas such as printed electronics will require the production of conductive lms or traces. Here, defect free graphene performs particularly well, giving high conductivity structures without high temperature post treatments. 5 Thus, it is clear that large scale production techniques for defect-free graphene are urgently required.Defect free graphene is generally produced by sonicating graphite powder either in certain solvents 9-16 or aqueous surfactant 17-23 solutions. The sonication tends to break up the graphite crystallites as well as exfoliating them to give large number of graphene nanosheets. 11 Raman spectroscopy 15,24,25 shows this method to produce negligible quantities of basal plane defects while XPS shows the akes to be un-oxidised. 14 While the graphene produced by this m...

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“…While some work has been done to separate dispersed flakes according to number of layers 7 , relatively little progress has been made on separation by lateral size. 12,13 We note that the lateral flake size can be very important when considering applications such as polymer reinforcement. 14,15 Size Exclusion Chromatography is a well-established chromatographic method for separating particles according to their size as they pass through porous gel filtration medium packed tightly into a column.…”

Section: Introductionmentioning

confidence: 99%

Lateral size selection of surfactant-stabilised graphene flakes using size exclusion chromatography

Smith

King

Wirtz

et al. 2012

Chemical Physics Letters

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Aqueous dispersions of graphene, stabilised by a surfactant, have been separated according to lateral flake size using size exclusion chromatography.Transition electron microscopy was used to characterise the flake size as a function of fraction number. While the stock dispersion had a mean lateral flake size of 0.6 m, the separated fractions displayed clear size separation, with the second and fourteenth fractions displaying mean sizes of ~1.2 and ~0.5 microns respectively. Raman spectroscopy shows the flake D:G intensity ratio to scale inversely with the flake size indicating that any defects present are associated with flake edges rather than basal plane defects.

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Size selection of dispersed, exfoliated graphene flakes by controlled centrifugation

Cited by 276 publications

References 48 publications

Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

Turbulence-assisted shear exfoliation of graphene using household detergent and a kitchen blender

Lateral size selection of surfactant-stabilised graphene flakes using size exclusion chromatography

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