Updated on 2024/02/25

写真a

 
KAWAI, Kosuke
 
Affiliation
Faculty of Science and Engineering, Waseda Research Institute for Science and Engineering
Job title
Junior Researcher(Assistant Professor)
Degree
Doctor ( 2021.03 The University of Tokyo )
Master ( 2018.03 The University of Tokyo )
Bachelor ( 2016.03 Kyoto University )
Mail Address
メールアドレス

Research Experience

  • 2021.07
    -
    Now

    Waseda University   Research Institute for Science and Engineering   Junior researcher

  • 2021.04
    -
    2021.06

    Waseda University   School of Advanced Science and Engineering   JSPS Research Fellowships for Young Scientists PD

  • 2020.04
    -
    2021.03

    The University of Tokyo   The Graduate School of Engineering   JSPS Research Fellowships for Young Scientists PD

  • 2016.10
    -
    2021.03

    The University of Tokyo

Education Background

  • 2018.04
    -
    2021.03

    The University of Tokyo   The Graduate School of Engineering   Department of Chemical System Engineering  

  • 2016.04
    -
    2018.03

    The University of Tokyo   The Graduate School of Engineering   Department of Chemical System Engineering  

  • 2012.04
    -
    2016.03

    Kyoto University   Faculty of Engineering   School of Industrial Chemistry  

Professional Memberships

  • 2023.01
    -
    Now

    The American Ceramics Society

  • 2019.01
    -
    Now

    公益社団法人 電気化学会

Research Areas

  • Inorganic materials and properties   蓄電材料

Awards

  • 電気化学会第87回大会優秀学生発表賞

    2020.03   公益社団法人 電気化学会  

 

Papers

  • Iron-based catholytes for aqueous redox-flow batteries

    Atsushi Okazawa, Takayuki Kakuchi, Kosuke Kawai, Masashi Okubo

    APL Materials   11 ( 11 ) 110901  2023.11  [Refereed]

     View Summary

    Redox-flow batteries (RFBs) are promising electrochemical energy storage devices to load-level intermittent power from renewable energy. In particular, aqueous RFBs using aqueous electrolytes possess several advantages over nonaqueous ones, such as low fabrication cost, nontoxicity, safety, and environmental benignity. Therefore, developing high-performance, abundant, less-expensive iron-based catholytes for aqueous RFBs is essential toward their wide deployment in a power grid. In this Perspective, we summarize the recent progress of iron-based catholytes for aqueous RFBs. We emphasize that iron-based catholytes possess widely ranged redox potentials (−1.0 to 1.5 V vs standard hydrogen electrodes) and solubility in water (0.2–4.0 mol L−1), thereby providing a wide range of cell performance. The molecular design, such as ligand functionalization, counter ion mixing, and asymmetrization, allows for rationally improving solubility, redox potential, and energy density. Furthermore, we demonstrate a simple evaluation method of the redox potential of iron-based catholytes using the calculated energy levels of the lowest unoccupied molecular orbital of ligand molecules. Finally, we rationalize the design strategy of iron-based catholytes for advanced aqueous RFBs.

    DOI

    Scopus

  • High-Voltage Electrochemical Properties of Lithium-Rich Spinel Oxides

    Kosuke Kawai, Takaaki Sudayama, Daisuke Asakura, Jun Kikkawa, Eriko Watanabe, Masashi Okubo, Atsuo Yamada

    The Journal of Physical Chemistry C   127 ( 26 ) 12428 - 12434  2023.06  [Refereed]

    Authorship:Lead author

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Influence of surface termination groups on electrochemical charge storage of MXene electrodes

    Kosuke Kawai, Masaki Fujita, Ryosei Iizuka, Atsuo Yamada, Masashi Okubo

    2D Materials   10 ( 1 ) 014012  2022.11  [Refereed]

    Authorship:Lead author

     View Summary

    Two-dimensional transition-metal carbides/nitrides (MXenes) have been intensively investigated as electrode materials for electrochemical energy storage devices, such as batteries and supercapacitors, due to their high capacitance, high-rate capability, and good cycle stability. Although MXenes possess various surface termination groups (e.g., -O, -OH, -F, -Cl, and -Br) that directly interact with adsorbed cations to exhibit charge transfer, the influence of each surface termination group on the electrochemical properties of MXene remains elusive because of difficulty in achieving exclusively modified termination. Herein, we report the electrochemical properties of MXenes with surface termination groups controlled by using fluorine-based aqueous solutions and molten salts as etchants. In aqueous electrolytes, Ti3C2Cl x and Ti3C2Br x synthesized using molten salts show no electrochemical activity in contrast to Ti3C2T x (T = O, OH, F, and Cl). Meanwhile, in a nonaqueous electrolyte, Ti3C2Cl x and Ti3C2Br x undergo amorphization upon the initial lithiation. These results suggest that the -O, -OH, and -F terminations play an important role in the electrochemical properties of MXene electrodes.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Kinetic square scheme in oxygen-redox battery electrodes

    Kosuke Kawai, Xiang-Mei Shi, Norio Takenaka, Jeonguk Jang, Benoit Mortemard de Boisse, Akihisa Tsuchimoto, Daisuke Asakura, Jun Kikkawa, Masanobu Nakayama, Masashi Okubo, Atsuo Yamada

    Energy & Environmental Science    2022.05  [Refereed]

    Authorship:Lead author

     View Summary

    Kinetic formation of the peroxo-like O22− dimer is identified as the origin of a voltage hysteresis in oxygen-redox battery electrodes.

    DOI

    Scopus

    17
    Citation
    (Scopus)
  • Lithium-Rich O2-Type Li0.66[Li0.22Ru0.78]O2 Positive Electrode Material

    Hirohito Umeno, Kosuke Kawai, Shin-ichi Nishimura, Daisuke Asakura, Masashi Okubo, Atsuo Yamada

    Journal of The Electrochemical Society   169 ( 4 ) 040536 - 040536  2022.04  [Refereed]

     View Summary

    Increasing the energy density of lithium-ion batteries is an important step towards flexible electricity supply, which can be achieved by developing large-capacity positive electrodes. Lithium-rich oxides have been a longstanding research target because of their large capacity involving extra oxygen-redox reactions. In this work, we report the synthesis, electrochemical properties, electronic structure, and structural evolution of O2-type lithium-rich layered oxide Li1.22‒xRu0.78O2. A robust Ru‒O layered framework without Ru migration allows for unveiling the solid-state electrochemistry of O2-type lithium-rich layered oxides with possibility of a large yet stable extra capacity for oxygen-redox reaction. Using a combination of X-ray photoelectron spectroscopy, X-ray absorption/emission spectroscopy, and in situ/ex situ X-ray diffraction, we clarified that O2-Li1.22‒xRu0.78O2 delivers a large capacity of 200 mAh g‒1 in association with Ru5+/Ru4+ and Ru4+/Ru3+ two-electron redox reactions under a solid-solution process, but with no contribution from the extra oxygen-redox reaction.

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Oxygen redox versus oxygen evolution in aqueous electrolytes: critical influence of transition metals

    Hirohito Umeno, Kosuke Kawai, Daisuke Asakura, Masashi Okubo, Atsuo Yamada

    Advanced Science     2104907  2022.02  [Refereed]

  • Square-Scheme Electrochemistry in Battery Electrodes

    Masashi Okubo, Kosuke Kawai, Zihan Ma, Atsuo Yamada

    Accounts of Materials Research   3 ( 1 ) 33 - 41  2021.11  [Refereed]

  • 4.7 V Operation of the Cr4+/Cr3+ Redox Couple in Na3Cr2(PO4)2F3

    Kosuke Kawai, Daisuke Asakura, Shin-ichi Nishimura, Atsuo Yamada

    Chemistry of Materials   33 ( 4 ) 1373 - 1379  2021.02  [Refereed]

    Authorship:Lead author

     View Summary

    Increasing the energy density of sodium-ion battery systems requires highvoltage cathode materials to compensate for the inherently higher redox potential of the Na/Na+ couple compared to the Li/Li+ couple (difference of 0.3 V). Distinct from the high-voltage (>4.2 V) operation using late transition metals (Co-3+Co-/(2+) or Ni3+/Ni2+) in previously reported polyanionic compounds, here we identify the record-high Cr4+/Cr3+ (3d(2)/3d(3)) redox potential in Na3-xCr2(PO4)(2)F-3 (0 < x < 1) at 4.7 V vs Na/Na+. Despite higher d-band position at early 3d transition metal with smaller effective nuclear charge compared to late transition metals, Cr 3d(t(2g)) in less than half-filled state possesses no energy level increments arising from crystal field splitting and intra-orbital Coulombic penalty, leading to extremely high voltages of the Cr4+/Cr3+ (3d(2)/3d(3)) redox couple.

    DOI

    Scopus

    8
    Citation
    (Scopus)
  • Nonpolarizing oxygen-redox capacity without O-O dimerization in Na2Mn3O7

    Akihisa Tsuchimoto, Xiang-Mei Shi, Kosuke Kawai, Benoit Mortemard de Boisse, Jun Kikkawa, Daisuke Asakura, Masashi Okubo, Atsuo Yamada

    Nature Communications   12 ( 1 ) 631  2021.01  [Refereed]

     View Summary

    <title>Abstract</title>Reversibility of an electrode reaction is important for energy-efficient rechargeable batteries with a long battery life. Additional oxygen-redox reactions have become an intensive area of research to achieve a larger specific capacity of the positive electrode materials. However, most oxygen-redox electrodes exhibit a large voltage hysteresis &gt;0.5 V upon charge/discharge, and hence possess unacceptably poor energy efficiency. The hysteresis is thought to originate from the formation of peroxide-like O22− dimers during the oxygen-redox reaction. Therefore, avoiding O-O dimer formation is an essential challenge to overcome. Here, we focus on Na2-<italic>x</italic>Mn3O7, which we recently identified to exhibit a large reversible oxygen-redox capacity with an extremely small polarization of 0.04 V. Using spectroscopic and magnetic measurements, the existence of stable O−• was identified in Na2-<italic>x</italic>Mn3O7. Computations reveal that O−• is thermodynamically favorable over the peroxide-like O22− dimer as a result of hole stabilization through a (σ + π) multiorbital Mn-O bond.

    DOI

    Scopus

    51
    Citation
    (Scopus)
  • Stabilization of a 4.5 V Cr4+/Cr3+ redox reaction in NASICON-type Na3Cr2(PO4)3 by Ti substitution

    Kosuke Kawai, Daisuke Asakura, Shin-ichi Nishimura, Atsuo Yamada

    Chemical Communications   55 ( 91 ) 13717 - 13720  2019.09  [Refereed]

    Authorship:Lead author

     View Summary

    <p>NASICON-type Na2CrTi(PO4)3 offers a stable redox reaction of Cr4+/Cr3+ at 4.5 V <italic>vs.</italic> Na/Na+.</p>

    DOI

    Scopus

    20
    Citation
    (Scopus)
  • High-Voltage Cr4+/Cr3+ Redox Couple in Polyanion Compounds

    Kosuke Kawai, Wenwen Zhao, Shin-ichi Nishimura, Atsuo Yamada

    ACS Applied Energy Materials   1 ( 3 ) 928 - 931  2018.02  [Refereed]

    Authorship:Lead author

    DOI

    Scopus

    54
    Citation
    (Scopus)

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Presentations

  • Data storage and analysis for optimal design of electrochemical energy storage devices

     [Invited]

    Presentation date: 2023.10

    Event date:
    2023.10
    -
    2023.11
  • Peroxide Formation for Voltage Hysteresis in O2-Type Lithium-Rich Layered Oxides

    K. Kawai, X.-M. Shi, N. Takenaka, J. Jang, B. Mortemard de Boisse, A. Tsuchimoto, D. Asakura, J. Kikkawa, M. Nakayama, M. Okubo, A. Yamada

    243rd ECS Meeting 

    Presentation date: 2023.05

    Event date:
    2023.05
    -
    2023.06
  • Exploration of cathode materials for high energy density rechargeable batteries

    Kosuke Kawai, Atsuo Yamada  [Invited]

    47th International Conference and Expo on Advanced Ceramics and Composites 

    Presentation date: 2023.01

    Event date:
    2023.01
     
     

Research Projects

  • 分子性イオンの導入により誘起される層状化合物MXeneの蓄電機能発現

    公益財団法人 池谷科学技術振興財団  2023年度 単年度研究助成

    Project Year :

    2023.04
    -
    2024.03
     

  • ナノ空間エンジニアリングに基づくレドックスキャパシタ電極の創製

    公益財団法人 徳山科学技術振興財団  2023年度 スタートアップ助成

    Project Year :

    2023.04
    -
    2024.03
     

  • 電極-電解液界面制御に基づく層状遷移金属炭化物MXene負極の創製

    公益財団法人 東電記念財団  2022年度研究助成(一般研究)

    Project Year :

    2023.04
    -
    2024.03
     

  • 層状遷移金属炭化物MXeneを用いた全固体電池の開発

    公益財団法人 岩谷直治記念財団  第49回(2022年度)研究助成

    Project Year :

    2023.04
    -
    2024.03
     

  • 水系蓄電デバイスの実現に向けた高容量Wadsley–Roth型酸化物負極の開発

    公益財団法人 大倉和親記念財団  2022年度 研究助成

    Project Year :

    2022.12
    -
    2024.03
     

  • Development of aqueous zinc rechargeable batteries with layered transition-metal carbides

    Waseda University  Research grant on comprehensive agreement of Mitsubishi Materials and Waseda University

    Project Year :

    2021.08
    -
    2022.02
     

  • Development of cathode materials exhibiting stable oxygen-redox reactions

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows

    Project Year :

    2020.04
    -
    2021.06
     

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