The formation of salts from graphite by strong acids

Hofmann, Ulrich; Rüdorff, W.

doi:10.1039/tf9383401017

Cited by 51 publications

(44 citation statements)

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“…The obtained x = 45 value for a stage 2 C x [CF 2 (CF 2 SO 2 ) 2 N] conforms to the long established observation of C x [anion], x = 24n, where n is the stage [16]. The obtained x = 52 for stage 3 GIC is relatively low and suggests that some interstaging between stages 2 and 3 occurs.…”

Section: Resultssupporting

confidence: 86%

Electrochemical preparation of graphite intercalation compounds containing a cyclic amide, [CF2(CF2SO2)2N]−

Özmen-Monkul

Lerner

Hagiwara

2009

Journal of Fluorine Chemistry

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Section: Resultssupporting

confidence: 86%

Electrochemical preparation of graphite intercalation compounds containing a cyclic amide, [CF2(CF2SO2)2N]−

Özmen-Monkul

Lerner

Hagiwara

2009

Journal of Fluorine Chemistry

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“…Although electrochemical intercalation has been known since the 19th century and is fundamental to the operation of, for example, lithium-ion and carbon-enhanced lead-acid batteries, the structure of ICs is not well understood. X-ray and electron diffraction data indicate that in many ICs 6 the intercalants organize in layers, and that these intercalant layers are themselves regularly spaced 7 . Transitioning from pristine to fully intercalated, a host crystal passes through stages, where ‘stage n ’ indicates n host layers separating each intercalant layer 1 , 7 .…”

Section: Introductionmentioning

confidence: 99%

Intercalation events visualized in single microcrystals of graphite

2017

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The electrochemical intercalation of layered materials, particularly graphite, is fundamental to the operation of rechargeable energy-storage devices such as the lithium-ion battery and the carbon-enhanced lead-acid battery. Intercalation is thought to proceed in discrete stages, where each stage represents a specific structure and stoichiometry of the intercalant relative to the host. However, the three-dimensional structures of the stages between unintercalated and fully intercalated are not known, and the dynamics of the transitions between stages are not understood. Using optical and scanning transmission electron microscopy, we video the intercalation of single microcrystals of graphite in concentrated sulfuric acid. Here we find that intercalation charge transfer proceeds through highly variable current pulses that, although directly associated with structural changes, do not match the expectations of the classical theories. Evidently random nanoscopic defects dominate the dynamics of intercalation.

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“…The GNP used in this work was a research grade (see below for preparation method) synthetized by AVANZARE (Navarrete, La Rioja, Spain) using a rapid thermal expansion of overoxidized-intercalated graphite (ox-GIC). The intercalation of graphite with sulphuric acid to obtain graphite-sulphate is a wellknown technology described for the first time by Hofmann and Rüdorff in 1938 [46]. In the present paper, the synthesis of GIC was made by adding 40 g of natural graphite flakes (average lateral size ≈ 1 mm) and 400 g of sulfuric acid (H2SO4) in a 5 liters refrigerated glass jacket reactor under continuous stirring at T < 10°C.…”

Section: 2synthesis Of Graphite Nanoplateletsmentioning

confidence: 99%

Effect of processing conditions on the thermal and electrical conductivity of poly (butylene terephthalate) nanocomposites prepared via ring-opening polymerization

et al. 2017

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Successful preparation of polymer nanocomposites, exploiting graphene-related materials, via melt mixing technology requires precise design, optimization and control of processing. In the present work, the effect of different processing parameters during the preparation of poly (butylene terephthalate) nanocomposites, through ring-opening polymerization of cyclic butylene terephthalate in presence of graphite nanoplatelets (GNP), was thoroughly addressed. Processing temperature (240°C or 260°C), extrusion time (5 or 10 minutes) and shear rate (50 or 100 rpm) were varied by means of a full factorial design of experiment approach, leading to the preparation of polybutylene terephthalate/GNP nanocomposite in 8 different processing conditions. Morphology and quality of GNP were investigated by means of electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry and Raman spectroscopy. Molecular weight of the polymer matrix in nanocomposites and nanoflake dispersion were experimentally determined as a function of the different processing conditions. The effect of transformation parameters on electrical and thermal properties was studied by means of electrical and thermal conductivity measurement. Heat and charge transport performance evidenced a clear correlation with the dispersion and fragmentation of the GNP nanoflakes; in particular, gentle processing conditions (low shear rate, short mixing time) turned out to be the most favourable condition to obtain high conductivity values. . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ ©2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ higher thermal conductivity [28,29]. In a recent paper, we demonstrated that the addition of hightemperature-annealed rGO in a polymer matrix leads to a thermal conductivity which is about 2-fold those of poly (butylene terephthalate) containing pristine rGO (higher defectiveness) or GNP [30], further confirming the need of high quality nanoflakes for the preparation of highly thermally conductive polymer nanocomposites. On the other hand, the control of GRM organization into a polymer matrix remains crucial in terms of nanoparticle distribution and quality of contacts between particles. Attempts in precisely controlling orientation and contacts between nanoparticles indeed resulted in an improvement of thermal transfer [31-33] but the methods adopted for the preparation of these nanocomposites are hardly up-scalable or requires very high filler concentrations. Finally, the reduction of interfacial thermal resistance was also pursued by nanoparticle functionalization [34][35][36], despite the effectiveness of this strategy may be also related to the lateral size of the nanoflakes [37]. Recently, the preparation of polymer nanocomposites was obtained by in-situ ring-opening polymerization of cyclic butylene terephthalate (CBT) oligomers into poly (butylene terephthalate), ...

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The formation of salts from graphite by strong acids

Cited by 51 publications

References 0 publications

Electrochemical preparation of graphite intercalation compounds containing a cyclic amide, [CF2(CF2SO2)2N]−

Electrochemical preparation of graphite intercalation compounds containing a cyclic amide, [CF2(CF2SO2)2N]−

Intercalation events visualized in single microcrystals of graphite

Effect of processing conditions on the thermal and electrical conductivity of poly (butylene terephthalate) nanocomposites prepared via ring-opening polymerization

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