Electroceramics in Japan IX

Paper Title Page

Authors: Hideyuki Morimoto, Kazuhiko Takeno, Yuuki Uozumi, Kenichi Sugimoto, Shinichi Tobishima
Abstract: Composite materials of β-FeOOH particles and carbon powder were prepared by hydrolyzing of FeCl3+Ti(SO4)2 (aq.) in which carbon powder was dispersed. β-FeOOH formed in the presence of Ti(IV) ions became amorphous and/or low crystallinity. The composite materials prepared in the presence of Ti(IV) ions worked as lithium intercalation electrodes in nonaqueous electrolytes including lithium ions. The electrodes exhibited a good cycle performance at large charge-discharge current density over 5 mA cm-2 ( 4 A g-1 per weight of active material). The composite materials are one of the promising candidates as electrode materials for energy storage devices, such as hybrid electrochemical supercapacitor, that require high-power operations.
Authors: Kenji Sakai, Kenji Fujimura, Shinzo Yoshikado
Abstract: TiO2 thin films for the dye sensitized solar cell have been deposited by the electrophoresis method using the ultra fine particles of TiO2. To adsorb much dye molecules on the TiO2 film, electrophoresis method and vacuum impregnation have been tried. The quality of TiO2 thin film and the amount of the dye molecules adsorbed on the thin film affect the energy conversion efficiency of the dye sensitized solar cell. The condition to adsorb large amounts of dye molecules on the TiO2 film was discussed. The values of open-circuit voltage and short-circuit current increased using both vacuum impregnation and electrophoresis method to adsorb dye molecules.
Authors: Shinya Suzuki, Seijiro Takahashi, Keigo Sato, Masaru Miyayama
Abstract: High-rate lithium intercalation properties of the Li-Mn-oxide synthesized by the reassembly of MnO2 nanosheets were examined. The colloidal suspension of MnO2 nanosheets was prepared by the exfoliation of proton-exchanged form of layered manganese oxide through the reaction with tetrabutylammonium hydroxide aqueous solution. The results of chemical analysis indicated that a Li-Mn-oxide had a chemical formula of Li0.31MnO2·0.05H2O. The discharge capacity of a Li-Mn-Oxide was 193 mAh/g initially, and decreased gradually during cycling. A Li-Mn-oxide exhibited the discharge capacity of 79 mAh/g at the current density of 2 A/g, and it was 52 % of 151 mAh/g at the current density of 50 mA/g.
Authors: Masahiro Kajitani, Motohide Matsuda, Akinori Hoshikawa, Takashi Kamiyama, Fujio Izumi, Michihiro Miyake
Abstract: Doping effects of Sr and/or Mg on the crystal structures of LaGaO3 perovskites were investigated. The doping with Mg into Ga-site in LaGaO3 led to structural change from the orthorhombic primitive lattice (Pbnm) to the orthorhombic body-centered lattice (Ibmm) at room temperature. The orthorhombic cell (Ibmm) of LaGa0.9Mg0.1O2.95 changed to the monoclinic (I2/a) by doping with Sr into La site. Neutron powder diffraction analyses revealed that these compounds had GaO6 octahedral tilt. The GaO6 octahedral tilt angles were reduced with doping with Sr and/or Mg.
Authors: Hajime Horikawa, Takashi Ogihara, Nobuo Ogata, Masahiro Asahara, Xing Zheng Wu
Abstract: Titania nanocrystals were prepared by hydrolysis of titanium alkoxide in ethanol solution. The preparation of titania / alumina thin film was performed on ITO coated glass substrate by dip coating method using ethanol of titania nanocrystal and boemite sol. The crystal structures, microstructure and thickness of titania / alumina thin film were examined by XRD and SEM. The adsorption of dye was influenced by the surface structure of thin film. The adsorption of dye on the films was improved by the immersion into acid as HNO3. Ruthenium polypyridyl complex and triarylmethylium salt were used as dye. Electrode using titania / alumina thin film for dye-sensitized solar cell was constructed.
Authors: Kenji Yoshihara, Takeshi Chuma, Morihiro Saito, Jun Kuwano, Hidenobu Shiroishi
Abstract: The O2-gas electrode (OGE) properties of the pyrochlores Pb2Ru2-XMXO7-δ(M=Mn,Fe,Co,Ni) [PRMx] were examined below 300°C with the cell of the type (PRMx | Ba0.975Ce0.8Gd0.2O3 (BCG) | PRMx). The PRMn electrodes showed good OGE properties comparable to those of Pb2Ru2O6.5 and superior to those of a Pt-paste electrode and the La0.6Sr0.4Co0.98Ni0.02O3 electrode, which are well-known representative OGEs. The results indicate that the PRMn electrodes can be used for OGEs in low-temperature applications including oxygen sensors.
Authors: Hiroaki Takeda, Satoshi Tanaka, Hiroyuki Shimizu, Takashi Nishida, Tadashi Shiosaki
Abstract: We report an effective substitution of aluminum for gallium in langasite-type La3Ta0.5Ga5.5O14 (LTG) crystals for use in a pressure sensor at high temperature. Al-substituted LTG (La3Ta0.5Ga5.5-xAlxO14; LTGAx) single crystals up to the solubility limit of x=0.5 have been grown by the conventional Czochralski technique. The electric properties of the LTGAx crystals were investigated and compared with those of LTG. By Al substitution, the piezoelectric constant d11 and the electromechanical coupling factors (k12) became slightly larger. The LTGAx crystals showed a lower temperature dependence of d11 and a higher electric resistivity ρ than those of the LTG crystals.
Authors: Takeshi Chuma, Haruhiko Toda, Morihiro Saito, Jun Kuwano, Hidenobu Shiroishi
Abstract: The O2-gas electrode (OGE) properties of the perovskite-related oxides SrFe1-x-yCoyRuxO3 (SFCR) were examined with the solid-state cells of the type (SFCR | Ba0.975Ce0.8Gd0.2O3 | SFCR) below 300°C. The SrFe0.7Co0.2Ru0.1O3 electrode showed the best OGE properties of the other SrFe1-x-yCoyRuxO3 (x0.2) electrodes prepared here. An oxide-ion current of 200 μA/cm2 was allowed to flow through the cell with the SFCR electrode at 225°C. The SFCR electrodes including some other compositions can be used instead of conventional Pt electrodes in solid-state cells at temperatures below 300°C.
Authors: Haruhiko Toda, Kenji Yoshihara, Morihiro Saito, Jun Kuwano, Hidenobu Shiroishi
Abstract: The O2-gas electrode (OGE) properties of the BaCe1-xGd0.2RuxO3-δ(BCGRx, x=0-0.45) oxides and the BaGd1-yRuyO3-δ(BGRy, y=0.5-1.0) oxides were examined with the cell of the type solid-state cell (OGE|BaCe0.8Gd0.2O3|OGE) below 300°C. Two single perovskite phases, BCGR0.15 in the BCGR series and BGR0.5 in the BGR series, exhibited OGE properties superior to those of known OGEs of Pt electrodes and La0.6Sr0.4Co0.98Ni0.02O3. Oxide-ion currents of the order of over one hundred μAcm-2 not yet reported were allowed to pass through the solid-state cell at low temperatures of ∼200°C.
Authors: Izumi Mukoyama, Kenichi Myoujin, Takashi Ogihara, Masao Uede, Hironori Ozawa, Kazunori Ozawa
Abstract: Spherical LiAlxMn2-xO4 fine powders were continuously produced by Internal Combustion Type Spray Pyrolysis Apparatus Using Gas Burner from metal nitrate precursor solutions. XRD showed that LiAlxMn2-xO4 powders were well crystallized in a spinel structure with the Fd3m space group. As-prepared powders have a spherical particle shape with a diameter of 2.3 μm. As-prepared samples were calcined at 800  for 10 h in air. The charge/discharge capacity of LiAlxMn2-xO4 was over 100 mAh/g. A powder production capacity speed of 1 kg/h was attained by this system.

Showing 51 to 60 of 66 Paper Titles