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Volume 2006 (2006)
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Volume 2006, Issue 221
Displaying 1-12 of 12 articles from this issue
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Akira Yoshida, Yutaka Kaburagi, Yoshihiro Hishiyama2006 Volume 2006 Issue 221 Pages 2-7
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn the field of Raman spectroscopy, it is known that the full width at half maximum intensity of the G band (G-FWHM) in the first order Raman spectrum for carbon material is a parameter for graphitization, though it is qualitative evidence. In the present paper, this fact has been studied quantitatively using pyrolytic carbons having various values of interlayer spacing doce, 0.3367 nm≤d002≤0.3421nm. The crystal structures of the pyrolytic carbon samples with 0.3367nm≤d002≤0.3374nm are graphitic structures, while the samples with 0.3374nm<d002≤0.3421nm are turbostratic structures. The first order Raman spectrum for each pyrolytic carbon sample has been measured on a cleaved surface of the basal plane of the sample using a Raman microprobe. It has been found that the G-FWHM value for the largest d002 value of 0.342nm of the sample is 21.5cm-1, the value remains at the almost constant value of about 21cm-1 for the d002 values down to 0.3374nm and then decreases almost linearly to the lowest value of 16cm-1 for the lowest d002 value of 0.3367nm. This trend almost agrees with the results obtained for benzene-derived vapor grown carbon fibers heat-treated up to 2900°C by Chieu and his coworkers. The results obtained can be related well to the observation with a scanning electron microscope on a cleaved surface and fractured surface perpendicular to the cleaved surface for each pyrolytic carbon sample. The present findings are also related very well to the magnetoresistance results for the same pyrolytic carbon samples published by Kaburagi and his coworkers.View full abstractDownload PDF (1986K) -
Hidetaka Konno, Daisuke Abe, Hiroki Habazaki2006 Volume 2006 Issue 221 Pages 8-13
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDifferent metal alkoxides were impregnated into exfoliated graphite (EG) by sorption and hydrolyzed with steam. Thus formed precursors were pyrolyzed at 1500-1700°C for 1-10h in argon to form single- and multi-component carbides, such as ZrC, TiC, (Ti, Zr) C solid solutions, TiC-ZrC composites, and TiC-Fe composites. In this process, hydrolyzed metal alkoxides were converted mainly to oxides and/or oxyhydroxides on the surface of graphite sheet composing EG, and eventually they are reduced to carbide or metal by graphite carbon at elevated temperatures. The small reaction spaces in EG produce fine metal carbide particles only by the pyrolysis. The process is simple and low cost, and possible to be developed to synthesize other carbides and composites.View full abstractDownload PDF (1714K) -
Kohsuke Kurakane, Katsuya Konno, Kaoru Onoe, Tatsuaki Yamaguchi2006 Volume 2006 Issue 221 Pages 14-18
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSActivated carbons were prepared from phenolic fiber with sodium hydroxide by means of heating with microwave plasma (MWP) of argon. The purpose of this paper is to elucidate the superiority of the MWP heating to the heating with microwave or electric furnace, as well as to investigate the development of the BET specific surface area with alkali by the MWP heating.
Carbon with a high specific surface area (over 2000m2/g) was obtained with a high yield (35 wt%) under the MWP heating within a very short time (10min) heating of phenolic fiber. The thermal efficiency on the solid phase could be considered as an effective factor. The increase of the surface area in a very short time could be attributed to the attack of active species in the MWP zone.View full abstractDownload PDF (3579K) -
Katsutomo Ohzeki, Yoshie Ohsaki, Boris Golman, Kunio Shinohara2006 Volume 2006 Issue 221 Pages 19-24
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe relationship was experimentally investigated between the cycle performance and the packing structure of a negative electrode film made of natural graphite particles of different tapping densities. At the same packing density of the electrode film, the modal voiddiameter and volumetric resistance increased with the tapping density of graphite powder. It was considered due to the fact that contact areas among particles of massive one were smaller than these of flaky one. Though the discharge capacity of the electrodes made of high tapping density powder rapidly decreased at low packing density, these cycle performances were satisfactorily improved with small irreversible capacity at high packing density.View full abstractDownload PDF (1387K) -
Noriko Yoshizawa2006 Volume 2006 Issue 221 Pages 25-30
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSActivated carbons and other types of porous carbons have attracted many attentions in several industrial fields currently. However, experimental results for characterization of the structure of porous carbons show no distinct features, and accordingly the structural information obtained from the experimental results has been limited to qualitative one. In this review, the author introduced some representative structure models of porous carbon materials from the crystallographic point of view. The progress in quantitative characterization of porous carbons by XRD and TEM was also introduced considering the application to energy storage devices.View full abstractDownload PDF (1737K) -
Yong Jung Kim, Kriengkamol Tantrakarn, Yusuke Abe, Takashi Yanagiura, ...2006 Volume 2006 Issue 221 Pages 31-39
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSWith increasing the concern to clean energy device, such as electric vehicle (EV), electric double layer capacitor (EDLC) is considered as an indispensable to recover the uneven load level required for practical operation in diverse applications when compared with other energy sources. The development of EDLCs has deep relation to the carbon materials with highly porous structure (>1000m2/g). Until now, contributions of carbon science to elucidating the relation between electrode and electrolyte have been enormous, and further achievement of future scientific studies on new forms of carbons, such as activated carbon, could afford even larger success in the development of EDLC. In this review, we depict the various parameters related to EDLC performance, on the basis of our research results. In particular, the size effect of the electrolyte ion, the morphological effects of active materials, are discussed.View full abstractDownload PDF (2756K) -
Shin R. Mukai, Hajime Tamon2006 Volume 2006 Issue 221 Pages 40-46
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSSi has a high ability to store Li+ and is expected to be used as the anode material in Li+ secondary batteries of the next generation. However, elemental Si cannot be used for this purpose, as it easily disintegrates due to the volume expansion induced by Li+ storage. This problem may be overcome by combining Si with other materials. The combination of Si with C seems to be quite promising, as both elements belong to the same group in the periodic table of the elements, and C also has a fairly high ability to store Li+. This article introduces two methods to synthesize Si/C composites designed to be used as anode materials for Li+ batteries, and characteristics of the materials obtained through them.View full abstractDownload PDF (2004K) -
[in Japanese], [in Japanese]2006 Volume 2006 Issue 221 Pages 47
Published: January 16, 2006
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSDownload PDF (154K) -
Norio Iwashita2006 Volume 2006 Issue 221 Pages 48-51
Published: January 16, 2006
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSX-ray diffraction techniques have been widely applied to the structural characterization of carbon materials and have given useful information. In 1963, the 117 Committee of the Japan Society for the Promotion of Sciences (Gakushin) specified standard procedures for the determination of lattice constants and crystallite sizes of carbon materials, especially graphitized materials. This specification has been called the “Gakushin” method and is commonly used in Japan.
Progress in computers has been remarkable, making the measurement of diffraction intensities and their corrections for different factors easier. In 2002, the 117 Committee began discussing the revision of the specification using the proposals of Dr. H. Fujimoto, in order to incorporate modem computing processes such as the automatic step-scanning measurements of diffraction intensities, profile fitting for diffraction lines, etc. On the basis of round-robin tests and their results and discussion, the specification of the Gakushin method was revised by a group of the 117 Committee. In this report, the revisions of the Gakushin method are introduced.View full abstractDownload PDF (907K) -
The 117 Committee of the Japan Society for the Pro2006 Volume 2006 Issue 221 Pages 52-60
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSPurpose: The purpose of this procedure is to standardize the procedure for the X-ray diffraction measurements of lattice parameters and crystallite sizes of carbon materials. This specification is expected to be used to characterize the structure not only in research laboratories but also in companies producing and using carbon materials. By utilizing the present procedure, more reliable and reproducible structural parameters could be measured, even though some of the determined parameters do not satisfy their exact scientific meanings. For example, the values of measured crystallite sizes depend not only on size of crystals but also on the strain in the crystals.
Abstract: This specification has been called the “Gakushin” method and has been commonly used in Japan. The method gave reliable values of lattice constants and crystallite sizes of carbon materials having a relatively high degree of graphitization. The diffraction peaks 002, 004, 110, 112 and 006 enabled us to compare data measured in different laboratories. The principal points of this specification are as follows: 1) the diffraction profiles observed must be corrected for the line broadening due to different intensity factors, such as X-ray absorption, Lorentz-polarization factors and the atomic scattering factor; 2) an internal standard of silicon must be used in order to avoid the shifting and broadening of diffraction profiles mainly due to the instrument used; and 3) a mixture of carbon sample with standard silicon must be packed in a thin sample holder for X-ray diffraction (0.2mm thickness).View full abstractDownload PDF (1686K) -
Koji Kuroda2006 Volume 2006 Issue 221 Pages 61-68
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (2978K) -
[in Japanese]2006 Volume 2006 Issue 221 Pages 75
Published: January 16, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (201K)
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