• Analytical Science and Technology
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• v.7 no.2
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• pp.193-199
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• 1994

We have synthesized K-CFICs by the modified two-bulb method. These synthesized compound were analysed with X-ray diffractometer and UV/VIS spectrophotometer. According to X-ray diffraction analysis, the intercalation of potassium between the carbon layers of carbon fiber was better then other intercalants. From obtained data for this deintercalation process, we can see that a number of potassiums were presented as a residue between the carbon layers and this residue compounds had a stability for a long term. Therefore, it is appear that these compounds have a capability as new useful material. From UV/VIS spectrometry data, we can suppose that spectrum of K-CFICs synthesized at $250^{\circ}C$ had only a $R_{min}$, and spectra of any other compounds were not appeared charecteristic peaks because potassium ions were little affect the energy levels of original carbon fiber.

• Journal of the Korean Ceramic Society
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• v.30 no.12
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• pp.1080-1088
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• 1993

The residue compounds of sulfuric acid-carbon fiber system were obtained from P100, M40, TZ307, and T300 fibers. The fibers which easily formed intercalation compound had small change of d002 value, but, large change of diameter of fiber. It was considered that the cracks in carbon fiber were due to the this conflicting result. The resistivities of residue compound of carbon fibers were increased with the large change of diameter of fibers. It is thought that the reason of our results is increasing defects such as crack in fibers. From the UV reflection spectra, it was found that reflectances of residue compounds were all decreased and the residue compounds were more stable than intercalation compounds.

• Analytical Science and Technology
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• v.8 no.2
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• pp.131-138
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• 1995

We have discussed on the structural transition and its effect on the electrical property of Li-GFDICs and Li-PCDICs occuring during the deintercalation process of Li-Graphite Fiber Intercalation Compounds(Li-GFICs) and Li-Petroleum Cokes Intercalation Compounds(Li-PCDICs) synthesized under pressure and temperature by spontaneous oxidation by air circulation. The analytical results were obtained by X-ray diffraction and electrical specific resistivity measurements. According to X-ray analysis, we have found that the major stage of Li-GFICs was stage 2 and those of Li-PCICs were stage 1 and stage 2, respectively. And from this results of the deintercalation process, we have found that the deintercalation process did not occur any more after 5th week of Li-GFDICs and after 3rd week of Li-PCDICs. According to the results of the electrical specific resistivity measurements, Li-GFDICs showed little variation to 3rd week and rising in the steady curve after 4th week, while Li-PCDICs showed a rising in the steady curve to 3rd week and a declining curve after 3rd week. Therefore from these results, we can consider that graphite fiber and petroleum cokes as a substrate can be also used as an anode material of battery because they have good intercalation-deintercalation reactivity with lithium.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.167-175
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• 1993

Lithium-Carbon Intercalation Compounds(Li-CICs) have been synthesized from various carbon ma-terials by use of the modified stainless steel two-bulbs methods. These compounds had various colours by structural character of starting materials. The synthesized Li-CICs were identified to stage formation process by X-ray diffraction data. At these results, well-oriented natural graphite and graphite fiber are formed lower stages(Stage 1, Stage 2), but poor-oriented carbon fiber and petroleum cokes are also formed higher stages(Stage 3, Stage 4, Stage 5). And when we compared with measured d value and calculated d value, these values agreed with each other. But poor-oriented carbon materials are some difference from them. The stage stability and energy stage of Li-CICs were obtained by UV/VIS Spectrophotometric data. X-ray diffraction and UV/VIS Spectrophotometric data suggested that well-oriented carbon materials has distingushible curve between energy and reflectance. In these results, we know that many charge carriers between carbon layers are related to concentration of intercalants. And then, this paper also provides information on high efficiency energy storing materials at intercalation process of Li-CICs.

• 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.