• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1113-1116
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• 1998

A new graphite intercalation compound (GIC), n-octylammonium tetrachlorofeffate(Ⅲ)-graphite, has been derived from well-known ferric chloride graphite intercalation compound. X-ray diffration study shows that the basal spacing of this new GIC is 20.8 Å. In order to investigate the local geometry around the iron atom in the graphite layers, X-ray absorption spectroscopy experiments were performed. The first discharge capacity of its exfoliated form is found to be 862 mAh/g, which is more than double the value of pristine graphite (384 mAh/g). Such a drastic increase implies that the exfoliated graphite is a promising electrode material.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.408-414
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• 1988

This thesis is 2nd thesis from "Mechanism of Intercalation Compounds in Graphite with Hydrogen sulfate(J. Korea Cer. Soc. Vol. 22. No.6, 1985). We have oxidized natural Graphite flakes(0.1~0.2mm., Kropfm hl passau in Deutchland. S40) with a solution of CrO3 in H2SO4. Whilst persulfate ions were intercalated, too, below 7$^{\circ}C$, no evidence for intercalation of a peroxo compound was found at 22$^{\circ}C$. The reaction was interrupted after various times by filtering and washing with concentrated H2SO4. X-ray diffraction showed that the 2nd stage compound had already been formed after 2 minutes. We could only follow further oxidation to the blue stage compound which was completed after 35 minutes. We have found six distinct intermediate stage between 2nd stage and 1 stage. Experiments are described on the formation of intermediate stage color and X-ray diffraction analysis.ysis.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1801-1805
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• 2002

The graphite intercalation compounds(GIC) were prepared by a dry process that led to the intercalation from the direct reaction of gaseous $SO_3$ with flake type graphite. The basal spacing of the GIC was increased from 8.3 ${\AA}$ to 12 in the gallery height. The ejection of interlayer $SO_3$ molecules by the heating for 1 minute at $950^{\circ}C$ resulted in an exfoliated graphite (EG) with surprisingly high expansion in the direction of c-axis. The expansion ratios of the exfoliated graphites were increased greatly between 220 times and 400 times compared to the original graphite particles, and the bulk density was range of 0.0053 to 0.01 $g/cm^3$, depending on reaction time. The pore size distribution of exfoliated graphite was in the range of $10-170{\mu}m$, which exhibites both mesoporosity and macroporosities. This result indicates that the direct reaction of graphite paricles with gaseous $SO_3$ can be proposed as an another route for the exfoliated graphite having excellent physical properties.

• Carbon letters
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• v.2 no.1
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• pp.55-60
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• 2001

Graphite intercalation compounds (GIC) were prepared by direct reaction of $SO_3$ gas with flake graphite. The intercalated $SO_3$ molecules were ejected by rapid heating to $950^{\circ}C$ under an oxidizing atmosphere for about 1 minute, resulting in surprisingly high expansion in the direction of c-axis. The characteristics of the micro-structure and pore size distribution were examined with a SEM and mercury intrusion porosimetry. The XRD analysis and spectroscopic analysis were used for the identification of the graphite and surface chemistry state. The pore size distribution of the exfoliated graphite (EG) was a range of $1{\sim}170{\mu}m$. The higher expanding temperature the higher expanded volume, so oil sorption capacities were 58.8 g of bunker-C oil and 34.7 g of diesel oil per 1 g of the the EG. The sorption equilibrium was achieved very rapidly within several minutes. As the treatment temperature increases, bulk density decreases.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.1-7
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• 2007

Electrorefining experiments were successfully carried out in LiCl-KCl eutectic molten salt with a graphite cathode. It was found that the formation of Uranium-Graphite intercalation compound(U-GIC) helped the self-scraping mechanism of the uranium dendrite and the efficiency of the electrorefiner increased due to an elimination of the stripping step. The contaminations of the uranium deposit by rare earth elements was negligible while about 300 ppm of carbon was observed. The carbon contamination is believed to be eliminated by further purification by yttrium reaction. The morphology characteristics of the recovered U deposit was compared to that of steel cathode. These are only qualitative preliminary experimental results, but we believe that further research on this type of activity change the direction of the electrorefining research on spent nuclear fuel.

• Composites Research
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• v.28 no.6
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• pp.389-394
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• 2015

The sound absorption coefficient and sound transmission loss of graphite intercalation compound (GIC) included epoxy composites were investigated. Epoxy resin was infused into the expanded GIC and the impedance tube method was employed to measure the sound absorption coefficient and sound transmission loss. Scanning electron microscopy photographs showed uniform distribution of the GIC in the epoxy matrix. The surface density of epoxy/GIC (20 wt%) composites decreased about 56% compared to that of pure epoxy. The sound absorption coefficient of composites increased about 3 times at the frequency range of 500~1000 Hz compared to the pure epoxy. The sound transmission loss of composites decreased with increasing the GIC content and it is attributed to the increase of pores in the composites.

• Carbon letters
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• v.26
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• pp.81-87
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• 2018

Morphological differences in multi-layered graphene flakes or graphene nanoplatelets prepared by oxidative (rGO-NP, reduced graphene oxide-nanoplatelets) and non-oxidative (GIC-NP, graphite intercalation compound-nanoplatelets) routes were investigated with various analytical methods. Both types of NPs have similar specific surface areas but very different structural differences. Therefore, this study proposes an effective and simple method to identify structural differences in graphene-like allotropes. The adsorptive potential peaks of rGO-NP attained by the density functional theory method were found to be more scattered over the basal and non-basal regions than those of GIC-NP. Raman spectra and high resolution TEM images showed more distinctive crystallographic defects in the rGO-NP than in the GIC-NP. Because the R-ratio values of the edge and basal plane of the sample were maintained and relatively similar in the rGO-NP (0.944 for edge & 1.026 for basal), the discrepancy between those values in the GIC-NP were found to be much greater (0.918 for edge & 0.164 for basal). The electrical conductivity results showed a remarkable gap between the rGO-NP and GIC-NP attributed to their inherent morphological and crystallographic properties.

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.768-774
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• 1993

Sulphuric acid was intercalated in mesophase pitch based graphite fiber (Thornel P100 of Amoco), PAN based graphite fiber (M40 of Thoray) and PAN based carbon fiber (T300 ofThoray, TZ307 of Taekwang in Korea) by 0.4wt% CrO3/H2SO4 solution. The degree of crystallization of fibers increased P100, M40, TZ307, T300 fiber in order and their d002 values were 3.384, 3.424, 3.470, 3.493$\AA$, respectively. After intercalation P100 fiber formed 1 stage compound whose d002 value was 3.994$\AA$(d001=7.988$\AA$). Other fibers showed (002) reflection belonging to their 1 stage comound and prinstine fiber.

• Analytical Science and Technology
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• v.7 no.3
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• pp.315-320
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• 1994

Li-GICs as a high performance energy storager were synthesized as a function of the Li content by the admixture and add-pressure method. The characteristics of these prepared compounds have been determined from the studies by X-ray diffraction, UV-VIS spectrometry and CHN analysis. It follows from the results of X-ray diffraction that the lower-stage intercalation compounds are formed as the Li contents increase, however the mixed stages in these compounds are also observed. In the case of the $Li_{40wt%}$, the compound with the structure of stage 1 has been predominently, but the structure of only stage 1 is not obtained. The $d_{001}$ value of stage 1 was determined to be ca. $3.70{\AA}$. An analysis of spectrometric data shows that each of the compounds gives distingushible energy state spectra. It is seen from the spectra that the positions of $R_{min}$ values, with increase in the Li contents, are shifted in the region of higher energy state. Such a result can be attributed to the formation of stable stages. The results of CHN analysis allow us to find the mixing state related to chemical compositions of the intercalated compounds and the superiority to admixture and add-pressure method. From the results determined, it reveals that $Li_{10wt%}$-GIC and $Li_{20wt%}$-GIC can be utilized for an anode of rechargable battery.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.660-666
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• 1998

We discussed structure, energy state, characteristics of thermal stability, and electrochemical properties of Li-GFICs, Li-PCICs, and Li-AGICs during the intercalation process. According to X-ray diffraction patterns, we observed phase of stage 2 mainly from Li-GFICs, while stage 1 phase as well as stage 2 from Li-PCICs. For the structure of Li-AGICs, stage 1 phase was dominant, but it was not possible to obtain pure stage 1 compound probably due to structural characteristics of artificial graphite. We measured energy state of the compounds to stage stability, and revealed that Li-AGICs and Li-GFICs were in more stable state than Li-PCICs. Therefore, those two compounds could be excellent candidate for energy reserve material. From the study of thermal degradation, Li-GFICs showed strong exothermic reaction at around 300 and $400^{\circ}C$. In the study of thermal stability of Li-AGIC at various temperatures, we observed that lithium was not completely deintercalated and high stage was maintained even at high temperature. In the case of charge, discharge, and electrochemical studies, Li-GFICs showed the best results.