研究者業績

Tatsuya Nakamura

  (中村 龍哉)

Profile Information

Affiliation
Professor (Doctor of Science), Graduate School, of Engineering, Division of Electronic Materials and Devices, University of Hyogo
Degree
(BLANK)(Hiroshima University)

J-GLOBAL ID
200901055102483640
researchmap Member ID
1000357821

Papers

 72
  • Hirotoshi Yamada, Tomoko Ito, Tatsuya Nakamura, Raman Bekarevich, Kazutaka Mitsuishi, Sanoop Palakkathodi Kammampata, Venkataraman Thangadurai
    Small, Apr 28, 2023  
  • Takeshi KAKIBE, Toshiki OHATA, Takumi SAITO, Reona HONDA, Satoshi MATSUDA, Tatsuya NAKAMURA, Hajime KISHI
    Electrochemistry, 90(3) 037006-037006, Mar 16, 2022  Peer-reviewed
  • T. Konya, Y. Kobayashi, T. Nakamura
    Solid State Ionics, 374 115820-115820, Dec 4, 2021  Peer-reviewed
  • Takahiro Saito, Kei Nishikawa, Tatsuya Nakamura, Shiro Seki
    The Journal of Physical Chemistry C, 124(31) 16758-16762, Aug 6, 2020  
    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, Oct, 2019  
    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, Mar 3, 2014  
  • NAKASHIMA Daisuke, NAKAMURA Tatsuya, YAMADA Yoshihiro
    Reports of Graduate School of Engineering, University of Hyogo, 57 22-27, Feb 28, 2005  
    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  
  • Transaction of the Material Research Society of Japan, 29 1663-1666, 2004  
  • 日本応用磁気学会誌, 28 757-765, 2004  

Major Books and Other Publications

 4

Presentations

 5

Teaching Experience

 12