研究者詳細 - 宇井　幸一

論文 - 宇井　幸一

分割表示 90 件中 41 - 60 件目／全件表示 >>

Cathode Performance of Lithium Non-stoichiometric Li[Li_x(Ni_1/3Co_1/3Mn_1/3)_1-x]O₂ Material for Li-ion Batteries

Jung-Min Kim, Naoaki Kumagai*, Yoshihiro Kadoma, Koichi Ui, and Hitoshi Yashiro

ITE Letters on Batteries, New Technologies & Medicine 7 ( 5 ) 454 - 457 2006年10月 [査読有り]

学術誌共著・分担

泳動電着法によるPb-Zr-Ti-Nb-Si-O系強誘電体厚膜の作製

井手本　康*, 吉田理志, 宇井幸一，小浦延幸

Electrochemistry 74 ( 11 ) 883 - 889 2006年11月 [査読有り]

学術誌共著・分担

密度汎関数理論計算を用いた溶融Li₂CO₃の局所構造解析

森田秀利, 大畑秀明, 竹内　謙, 宇井幸一, 小沢幸三, 小浦延幸*

Electrochemistry 75 ( 6 ) 466 - 471 2007年06月 [査読有り]

学術誌共著・分担

Fabrication of Electrode for Capacitor Cell Prepared by Electrophoretic Deposition Method

Koichi Ui*, Kazuma Okura, Nobuyuki Koura, Satoru Tsumeda, and Kenji Tamamitsu

Electrochemistry 75 ( 8 ) 604 - 606 2007年08月 [査読有り]

学術誌共著・分担

Equilibrium Geometries and Structural Stability of the Al_mNa_n (m=2-4; n=1-8) Clusters

Hidenori Matsuzawa*, Kazuhiro Sato, Takuji Hirata, Koichi Ui, and Nobuyuki Koura

J. Chem. Theory Comput. ( American Chemical Society ) 3 ( 5 ) 1818 - 1829 2007年09月 [査読有り]

学術誌共著・分担

The stable geometries and formation processes of the AlmNan (m = 2-4; n = 1-8) clusters were investigated using the density functional theory (DFT). The Alm (m = 2-4) structures are maintained in the clusters. The Na atoms are attached to the Al-Al bond or Al plane for less than n = 4 in the AlmNan (m = 2-4) clusters. The odd electron of the attached Na atom is transferred to the Alm part for n 4 or 5 in the AlmNan (m = 2-4) clusters since the Alm part becomes stable. The Na-Na bonding is formed by the attached Na atom after saturation of the Al-Al bonds or Al atoms. The Al2Na5, Al3Na5, Al3Na6, Al3Na7, and Al3Na8 clusters have a characteristic structure. The Na wing is formed in the Al3Nan (n = 5-8) clusters. The 2S shell containing the 3s orbital of the Na atom and the 3p orbital of the Al atom becomes stable before the occupation of the 1D shell because the electrons are delocalized on the Na plane for n 5 in the AlmNan (m = 2-4) clusters. The stability of the AlmNan (m = 2-4; n = 1-8) clusters was evaluated by comparison of the vertical ionization potential (IP), HOMO-LUMO gap, adsorption energy of the Na atom, and binding energy per atom.

DOI

Electrochemical Properties of Li_1+x(Ni_0.4Co_0.2Mn_0.4)_1-xO₂ (x = 0.00 and 0.05) for Lithium-ion Batteries

Jung-Min Kim, Yoshihiro Kadoma, Koichi Ui, and Naoaki Kumagai*

ITE Letters on Batteries, New Technologies & Medicine 8 ( 5 ) B12 - B16 2007年10月 [査読有り]

学術誌共著・分担

ジメチルエーテルを直接燃料に用いた中温作動型SOFC用新規アノード触媒の開発

竹内　謙*, 石田洋介, 粕谷健太, 田井良典, 古屋仲秀樹, 宇井幸一, 小浦延幸

Electrochemistry 75 ( 10 ) 786 - 790 2007年10月 [査読有り]

学術誌共著・分担

Improvement of Electrochemical Characteristics of Natural Graphite Negative Electrode Coated with Polyacrylic Acid in Pure Propylene Carbonate Electrolyte

Koichi Ui, Shinei Kikuchi; Fuminobu Mikami; Yoshihiro, Kadoma, and Naoaki Kumagai*

J. Power Sources 173 ( 1 ) 518 - 521 2007年11月 [査読有り]

学術誌共著・分担

In order to improve the negative electrode characteristics of a graphite electrode in a propylene carbonate (PC)-containing electrolyte, we have prepared a graphite negative electrode coated with a water-soluble anionic polymer as a binder for composite graphite electrodes. The electrochemical characteristics of the coated graphite were evaluated by cyclic voltammetry and charge–discharge cycle tests. The coated graphite negative electrode showed a stable Li+ ion intercalation/deintercalation reaction without the exfoliation of the graphene layers caused by the co-intercalation of the PC solvent in the LiClO4/PC solution. The charge–discharge characteristic of the coated graphite negative electrode in a PC-containing electrolyte was almost the same as that in ethylene carbonate-based electrolyte.

DOI

エチレングリコールを混合したZnCl₂-NiCl₂-EMIC常温型溶融塩浴を用いたクラックフリー非晶質Zn-Ni合金の電析

小浦延幸,上浦尚子,竹内　謙, 宇井幸一, 山崎貴司

表面技術 58 ( 11 ) 682 - 688 2007年11月 [査読有り]

学術誌共著・分担

Synthesis of Hollandite-type Li_xMnO₂ by Li⁺ ion-exchange in molten salt and lithium insertion characteristics

Yoshihiro Kadoma, Satoru Oshitari, Koichi Ui, and Naoaki Kumagai*

Electrochim. Acta. 53 ( 4 ) 1697 - 1702 2007年12月 [査読有り]

学術誌共著・分担

Structural and Electrochemical Properties of Li⁺ Ion-exchanged Hollandite-type MnO₂ for Lithium-ion Batteries

Yoshihiro Kadoma, Naoaki Kumagai*, Satoru Oshitari, and Koichi Ui

ITE Letters on Batteries, New Technologies & Medicine 8 ( 6 ) 674 - 678 2007年12月 [査読有り]

学術誌共著・分担

Electroless Plating of Aluminum from a Room-Temperature Ionic Liquid Electrolyte

Nobuyuki Koura*, Hiroshi Nagase, Atsushi Sato, Shintaro Kumakura, Ken Takeuchi, Koichi Ui, Tetsuya Tsuda, and Chun K. Loong

J. Electrochem. Soc. 155 ( 2 ) D155- - D157 2008年02月 [査読有り]

学術誌共著・分担

Because aluminum is a less-noble metal which has the standard electrode potential of −1.676 V vs normal hydrogen electrode, it is impossible to obtain the electrodeposition of aluminum from an aqueous solution. No one has reported an electroless plating method of aluminum. We succeeded in demonstrating the electroless plating of aluminum from a room-temperature ionic liquid (RTIL). It was found from measurements of inductively coupled plasma, X-ray diffraction, scanning electron microscopy (SEM), SEM-energy-dispersive X-ray analysis, and glow discharge optical emission spectroscopy that dense, smooth, and pure aluminum plating was obtained from the RTIL by the electroless plating method. Moreover, the reaction mechanism of the electroless plating of aluminum from the RTIL electrolyte was electrochemically analyzed.

DOI

Structural Modification of Li[Li_0.27Co_0.20Mn_0.53]O₂ by Lithium Extraction and its Electrochemical Property as the Positive Electrode for Li-ion Batteries

Naoaki Kumagai*, Jung-Min Kim, Syo Tsuruta, Yoshihiro Kadoma, and Koichi Ui

Electrochim. Acta. 53 ( 16 ) 5287 - 5293 2008年06月 [査読有り]

学術誌共著・分担

DOI

Development of Non-flammable Lithium Secondary Battery with Room-temperature Ionic Liquid Electrolyte -Performance of Electroplated Al film negative electrode-

Koichi Ui*, Keigo Yamamoto, Kohei Ishikawa, T. Minami, Ken Takeuchi, Masayuki Itagaki, Kunihiro Watanabe, and Nobuyuki Koura

J. Power Sources 183 ( 1 ) 347 - 350 2008年08月 [査読有り]

学術誌共著・分担

DOI

A rechargeable lithium metal battery operating at intermediate temperatures using molten alkali bis(trifluoromethylsulfonyl)amide mixture as an electrolyte

Atsushi Watarai, Keigo Kubota, Masaki Yamagata, Takuya Goto, Toshiyuki Nohira, Rika Hagiwara, Koichi Ui, Naoaki Kumagai

J. Power Sources 183 724 - 729 2008年08月 [査読有り]

学術誌共著・分担

Characterization and electrochemical properties of Li⁺ ion-exchanged products of hollandite-type K_y(Mn_1-xCo_x)O₂ for rechargeable lithium battery electrodes

Yoshihiro Kadoma, Satoru Oshitari, Koichi Ui, and Naoaki Kumagai*

Solid State Ionics 179 1710 - 1713 2008年09月 [査読有り]

学術誌共著・分担

Development of the Fe-Ni Anodic Catalyst for Solid Oxide Fuel Cell Operated at　Intermediate- temperature Direct Utilizing of Dimethylether Fuel

Ryosuke Tai, Koichi Ui, Ken Takeuchi*, Kenjiro Fujimoto, and Shigeru Ito

Electrochemistry 77 ( 2 ) 149 - 151 2009年02月 [査読有り]

学術誌共著・分担

ジメチルエーテルを直接燃料に用いた中温作動型SOFC用Fe触媒の開発