研究者業績

中村 龍哉

ナカムラ タツヤ  (Tatsuya Nakamura)

基本情報

所属
兵庫県立大学 大学院 工学研究科 電気系工学専攻 物性・デバイス部門 教授 (博士(理学))
学位
博士(理学)(広島大学)

J-GLOBAL ID
200901055102483640
researchmap会員ID
1000357821

論文

 72
  • Hirotoshi Yamada, Tomoko Ito, Tatsuya Nakamura, Raman Bekarevich, Kazutaka Mitsuishi, Sanoop Palakkathodi Kammampata, Venkataraman Thangadurai
    Small 2023年4月28日  
  • Takeshi KAKIBE, Toshiki OHATA, Takumi SAITO, Reona HONDA, Satoshi MATSUDA, Tatsuya NAKAMURA, Hajime KISHI
    Electrochemistry 90(3) 037006-037006 2022年3月16日  査読有り
  • T. Konya, Y. Kobayashi, T. Nakamura
    Solid State Ionics 374 115820-115820 2021年12月4日  査読有り
  • Takahiro Saito, Kei Nishikawa, Tatsuya Nakamura, Shiro Seki
    The Journal of Physical Chemistry C 124(31) 16758-16762 2020年8月6日  
    The research and development of secondary batteries, such as the lithium-ion batteries, have been widely conducted. Most electrodes are of composite type and comprise an active material, a conductive additive, and a binder. To achieve a precise analysis of electrochemical properties for only an active material, electrochemical measurement of a single particle of an active material was carried out using an ultramicroelectrode in an Ar-filled glovebox under an inert atmosphere. Although detection of cyclic voltammetry and resistance values of LiCoO2 (LCO) secondary particles has been reported using a single-particle electrode, we succeeded in achieving the first detailed analysis of capacity and resistance components of a single active material particle by charge-discharge and alternating current impedance measurements using LCO primary particles to elucidate the battery reaction process. The capacity values of LCO single particles were detected in units of mA h g-1, whose values were close to the theoretical capacity values of LCO single particles based on their mass and size. The resistance components of an LCO single particle were detected by alternating current impedance spectroscopy, which cannot be measured in conventional electrode systems, such as applied sheet materials. A resistance model for the active material is proposed.
  • Takayuki Konya, Yuji Shiramata, Tatsuya Nakamura
    BUNSEKI KAGAKU 68(10) 793-800 2019年10月  
    An electrochemical cell with a specifically designed X-ray window was fabricated in order to evaluate the structural evolution of the cathode material under the operating condition. It enabled us to obtain strong signals from a positive electrode material without a significant loss of the battery function. With use of this system, the structure evolution during the charge-discharge process of a layered cathode material Li[Ni1/3Co1/3Mn1/3]O-2 and a high voltage spinel cathode LiMn1.5Ni0.5O4 was studied. It was found from the experimental results that the Li [Ni1/3Co1/3Mn1/3]O-2 cathode exhibited a single-phase reaction, where the lattice parameters continuously changed. In the case of LiMn1.5Ni0.5O4 cathode, the charge-discharge reaction proceeded in two continuous two-phase reactions. Especially for the latter, the phase evolution was reversible in the low- current density reaction. On the other hand, in the high current density charge-discharge reaction, asymmetric behavior was observed. This means that the kinetic limitation of the battery reaction is observable even in this laboratory X-ray diffraction system.

MISC

 39
  • 高原晃里, 石神龍哉, 児玉憲治, 古城篤志, 安田啓介, 中村龍哉, 岡好浩
    応用物理学会春季学術講演会講演予稿集(CD-ROM) 61st ROMBUNNO.17A-D6-4 2014年3月3日  
  • 中島 大輔, 中村 龍哉, 山田 義博
    兵庫県立大学大学院工学研究科研究報告 57 22-27 2005年2月28日  
    Lithium-nickel layered oxides were prepared by the solid-state reaction at temperature range of 700-850℃ in O_2 atmosphere. The structural refinement with the help of Rietveld analysis showed that the crystal structure of these compounds were identified as α-NaFeO_2 type layered rock-salt, where some extra Ni ions were present in Li-layers. As the Ni content in the Li-layer increased, the lattice parameter a increased and the ratio of C/a decreased. From the magnetic susceptibility measurement, it was found that both the asymptotic Curie temperature and the spontaneous magnetization at low temperature are sensitive to the presence of extra Ni ions in Li-layers. The asymptotic Curie temperature, which was always positive, shifted toward higher temperature with an increase in the non-stoichiometry degree. It was seen that the spontaneous magnetization 4.2K is also enhanced with the non-stoichiometry. Considering these magnetic variation with the non-stoichiometry enabled us to propose the following model; Ni-Ni magnetic coupling within the transition metal layer was weak and ferromagnetic, whereas the inter-layer Ni-Ni coupling is relatively strong and antiferromagnetic. The increase in the asymptotic Curie temperature may be attributed to the development of magnetic correlation from two to three dimension, and the enhancement of the spontaneous magnetization is described by ferromagnetic cluster formation.
  • Transaction of the Material Research Society of Japan 29 1683-1686 2004年  
  • Transaction of the Material Research Society of Japan 29 1663-1666 2004年  
  • 日本応用磁気学会誌 28 757-765 2004年  

主要な書籍等出版物

 4

講演・口頭発表等

 5

担当経験のある科目(授業)

 12