Masaya Kodama

Novel synthesis of polymer and carbonaceous nanomaterials via a micelle/silicate nanostructured precursor

Mesoporous carbonaceous materials with relatively high surface area have been synthesized by a new method composed of in situ polymerization of divinylbenzene in the hydrophobic phase of a hexagonally arrayed micelle/silicate nanocomposite and subsequent carbonization and hydrofluoric acid treatments, while rod-like carbons were obtained from a direct incorporation of divinylbenzene into the mesopores of MCM-41.

Phase transition in porous electrodes. III. For the case of a two component electrolyte.

The electrochemical thermodynamics of electrolytes in porous electrodes is qualitatively different from that in the bulk with planar electrodes when the pore size is comparable to the size of the electrolyte ions. In this paper, we discuss the thermodynamics of a two component electrolyte in a porous electrode by using Monte Carlo simulation. We show that electrolyte ions are selectively adsorbed in porous electrodes and the relative concentration of the two components significantly changes as a function of the applied voltage and the pore size. This selectivity is observed not only for the counterions but also for the coions.

Electrochemical Behavior of Halogen-Doped Carbon Materials as Capacitor Electrodes

Electric double-layered capacitor (EDLC) usually uses high-surface area carbon materials as the electrodes, and the authors have reported that single-walled carbon nanotube (SWCNT) is a promising material for the electrode of EDLC [1-3]. For the further improvement of capacitance, modification of the electrode carbon materials is important. Doping is one of the methods to modify the carbons, and lithium doping is a recent hot topic to modify the negative carbon electrode which is the core technique of so-called lithium-ion capacitor. On the other hand, some of halogen is known to react with carbon strongly with p-doping. In particular, p-doping of SWCNT by bromine and iodine vapor has been investigated widely from the viewpoints of increase the carrier of SWCNT. We focus the p-doping by halogens to challenge the modification of positive carbon electrodes for capacitor system. In the present work, bromine and iodine vapors were reacted with various carbon materials such as SWCNT, graphite, and activated carbon to modify their electronic states, and their electrochemical behaviors in 1M Et4NBF4/PC were investigated, paying attentions to their capacitance, initial potential, and cyclic reversibility.

Stabilization of pitch derived ultrafine particles by iodine treatment

Hisashi Kajiura*, Yasuhiro Tanabe, Masaya Kodama** and Eiichi Yasuda (Received April 17, 1996) Materials and Structures Laboratory, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku, Yokohama 226, Japan *Research Fellow of the Japan Society for the Promotion of Science **Inorganic Composite Materials Department , Kyushu National Industrial Research Institute Shuku-machi, Tosu-city, Saga 841, Japan

Novel carbon structure prepared using mica as template

A fluorine expandable mica (EM), having two-dimensional spread in its crystal form, was used as a template for carbonization of organic liquids such as quinoline and pyridine. Despite Intrinsic volatile under the ambient pressure, these organic liquids inserted into the interlayer space of mica yielded carbonaceous compound after heat treatment over 500°C in inert atmosphere. The particle size of the compound separated from the mica layer depends on that of mica as a template. Detailed TEM observation revealed unique structure, namely each particle comprised two structural parts: film and surrounding rim part. The film part was very thin, thus being transparent for SEM observation and rim part has constant width of about 20 nm. This structure is particularly interesting, because it can be carbon thin film supported by carbon micro-ring.

Ultrafine magnetic metal dispersed carbons prepared from anisotropic pitch and metal acetylacetonate complexes

Transition metal (Fe, Co or Ni) dispersed carbon composites were prepared using the mixtures of metal acetylacetonate complex as a source of metal particles and an anisotropic coal-tar pitch as a carbon matrix precursor by heat treatment at the temperatures up to 1000°C. Mixing of the metal complexes and the pitch by dissolving in quinoline permitted the notable fine dispersion of the complex in the pitch. Then the resulting mixtures were easily converted to the metal dispersed carbons by pyrolysis under an inert atmosphere. The appeared particles were Fe3O4/α-Fe/Fe3C, β-Co or Ni when using the corresponding metal complex. Besides, their particle diameters were much less than 30 nm and distributed evenly throughout the carbon matrix. The magnetic properties of the metal dispersed carbons were evaluated with a vibrating sample magnetometer, and it was found that saturation magnetization and coercive force ranged from 1.03 × 10−5 to 5.65 × 10−5 Wb · m/kg and from 0.21 × 104 to 3.06 × 104 A/m, respectively.