Tomoya Kawaguchi

Materials Scientist

About

photo of me

Hi. I, Tomoya Kawaguchi, Ph.D. is a materials scientist and assistant professor of Institute for Materials Research, Tohoku University in Japan.
See Career for more detail.

My research interests are developing oxide materials for rechargeable batteries such as lithium-ion batteries and magnesium rechargeable batteries based on a concept of nanodomain  microstructure.
See Research for more detail.

Let’s work together.

Research

Develop energy materials

Sustainable society and electric vehicles are facilitated by battery technology; improving battery capacity is one of the social urgent issues today. Transition metal oxide materials are currently used for cathodes of lithium-ion batteries and magnesium rechargeable batteries, facing the intrinsic capacity limit determined by valence change of constituent transition metals. To tackle this problem, I study on strain effect yielded by a nano-domain microstructure in the oxide electrodes, which is expected to unlock large capacity delivered by anionic (e.g., oxygen and sulfur) reduction/oxidation (redox) reaction as well as the conventional cationic reaction.

Unveil subtle difference in “colors” of atoms

“Colors” of an atom in an X-ray region tell us a chemical state of the atom, which is one of the most important clues to understand the origin of materials properties. I have studied on resonant X-ray diffraction spectroscopy, which is a so-called coupling of X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS and also called as XAFS). This technique enables to reveal valence states and local structure of an element at each crystallographic site and phase. I developed a fast measurement technique of diffraction anomalous fine structure (DAFS) and a direct analysis using the logarithmic dispersion relation. This technique was applied to a battery material for the first time, which revealed a degradation mechanism of the first charge/discharge cycle of lithium-ion batteries.

Image material surface and inside

An electrochemical reaction proceeds surface of a material while it also drastically changes inside of the material. Understanding both of them are of great importance to design the material. I developed a direct analysis technique for crystal truncation rod (CTR) analysis, which is so sensitive to the surface that even a single layer change on the surface can be detected. I am also working with Bragg coherent diffraction imaging (BCDI) of an electrode material.

Publication

Journal articles

2019

Gas-induced segregation in Pt-Rh alloy nanoparticles observed by in situ Bragg coherent diffraction imaging

Tomoya Kawaguchi, Thomas F. Keller, Henning Runge, Luca Gelisio, Christoph Seitz, Young Y. Kim, Evan R. Maxey, Wonsuk Cha, Andrew Ulvestad, Stephan O. Hruszkewycz, Ross Harder, Ivan A. Vartanyants, Andreas Stierle, Hoydoo You

Gas-induced segregation in Pt-Rh alloy nanoparticles observed by in situ Bragg coherent diffraction imaging Journal Article Forthcoming

Physical Review Letters, Forthcoming.

Abstract | Links

Study of the Internal Compositions of Binary Alloy Pd-Rh Nanoparticles by Using Bragg Coherent Diffraction Imaging

Tomoya Kawaguchi, Wonsuk Cha, Vitalii Latyshev, Serhii Vorobiov, Vladimir Komanicky, Hoydoo You

Study of the Internal Compositions of Binary Alloy Pd-Rh Nanoparticles by Using Bragg Coherent Diffraction Imaging Journal Article

Journal of the Korean Physical Society, 75 (7), pp. 528-533, 2019.

Abstract | Links

High Anionic Conductive Form of PbxSn2–xF4

Miwa Murakami, Yoshiyuki Morita, Masao Yonemura, Keiji Shimoda, Masahiro Mori, Yukinori Koyama, Tomoya Kawaguchi, Katsutoshi Fukuda, Yoshihisa Ishikawa, Takashi Kamiyama, Yoshiharu Uchimoto, Zempachi Ogumi

High Anionic Conductive Form of PbxSn2–xF4 Journal Article

Chemistry of Materials, 31 (18), pp. 7704-7710, 2019.

Abstract | Links

Anomalous Antiferromagnetism in Metallic RuO2 Determined by Resonant X-ray Scattering

Zhihai H. Zhu, Joerg Strempfer, Reshma R. Rao, Connor A. Occhialini, Jonathan Pelliciari, Yongseong Choi, Tomoya Kawaguchi, Hoydoo You, John F. Mitchell, Yang Shao-Horn, and Riccardo Comin

Anomalous Antiferromagnetism in Metallic RuO2 Determined by Resonant X-ray Scattering Journal Article

Phycal Review Letters, 122 , pp. 017202, 2019.

Abstract | Links

Electrochemical phase transformation accompanied with Mg extraction and insertion in a spinel MgMn2O4 cathode material

Takuya Hatakeyama, Norihiko L Okamoto, Kohei Shimokawa, Hongyi Li, Aiko Nakao, Yoshiharu Uchimoto, Hiroshi Tanimura, Tomoya Kawaguchi, Tetsu Ichitsubo

Electrochemical phase transformation accompanied with Mg extraction and insertion in a spinel MgMn2O4 cathode material Journal Article

Phys. Chem. Chem. Phys., 21 , pp. 23749-23757, 2019.

Abstract | Links

2018

Dynamics of the Photoinduced Insulator-to-Metal Transition in a Nickelate Film

Vincent Esposito, Laurenz Rettig, Elisabeth M. Bothschafter, Yunpei Deng, Christian Dornes, Lucas Huber, Tim Huber, Gerhard Ingold, Yuichi Inubushi, Tetsuo Katayama, Tomoya Kawaguchi, Henrik Lemke, Kanade Ogawa, Shigeki Owada, Milan Radovic, Mahesh Ramakrishnan, Zoran Ristic, ValerioScagnoli, Yoshikazu Tanaka, Tadashi Togashi, Kensuke Tono, Ivan Usov, Yoav W. Windsor, Makina Yabashi, Steven L. Johnson, Paul Beaud, Urs Staub

Dynamics of the Photoinduced Insulator-to-Metal Transition in a Nickelate Film Journal Article

Structural Dynamics, 5 , pp. 064501, 2018.

Abstract | Links

A Reversible Rocksalt to Amorphous Phase Transition Involving Anion Redox

Atsushi Sakuda, Koji Ohara, Tomoya Kawaguchi, Katsutoshi Fukuda, Koji Nakanishi, Hajime Arai, Yoshiharu Uchimoto, Toshiaki Ohta, Eiichiro Matsubara, Zempachi Ogumi, Kentaro Kuratani, Hironori Kobayashi, Masahiro Shikano, Tomonari Takeuchi, Hikari Sakaebe

A Reversible Rocksalt to Amorphous Phase Transition Involving Anion Redox Journal Article

Scientific Reports, 8 (1), pp. 15086, 2018, ISBN: 4159801833518.

Abstract | Links

Site-Selective Analysis of Nickel-Substituted Li-Rich Layered Material: Migration and Role of Transition Metal at Charging and Discharging

Hideyuki Komatsu, Taketoshi Minato, Toshiyuki Matsunaga, Keiji Shimoda, Tomoya Kawaguchi, Katsutoshi Fukuda, Koji Nakanishi, Hajime Tanida, Shunsuke Kobayashi, Tsukasa Hirayama, Yuichi Ikuhara, Hajime Arai, Yoshio Ukyo, Yoshiharu Uchimoto, Eiichiro Matsubara, Zempachi Ogumi

Site-Selective Analysis of Nickel-Substituted Li-Rich Layered Material: Migration and Role of Transition Metal at Charging and Discharging Journal Article

J. Phys. Chem. C, 122 (35), pp. 20099-20107, 2018, ISSN: 1932-7447.

Abstract | Links

Strain-Induced Stabilization of Charged State in Li-Rich Layered Transition Metal Oxide for Lithium Ion Batteries

Tomoya Kawaguchi, Masashi Sakaida, Masatsugu Oishi, Tetsu Ichitsubo, Katsutoshi Fukuda, Satoshi Toyoda, Eiichiro Matsubara

Strain-Induced Stabilization of Charged State in Li-Rich Layered Transition Metal Oxide for Lithium Ion Batteries Journal Article

J. Phys. Chem. C, 122 (34), pp. 19298–19308, 2018, ISSN: 1932-7447.

Abstract | Links

Analysis of the Discharge/Charge Mechanism in VS4 Positive Electrode Material

Kazuto Koganei, Atsushi Sakuda, Tomonari Takeuchi, Hikari Sakaebe, Hironori Kobayashi, Hiroyuki Kageyama, Tomoya Kawaguchi, Hisao Kiuchi, Koji Nakanishi, Masashi Yoshimura, Toshiaki Ohta, Toshiharu Fukunaga, Eiichiro Matsubara

Analysis of the Discharge/Charge Mechanism in VS4 Positive Electrode Material Journal Article

Solid State Ionics, 323 , pp. 32–36, 2018, ISSN: 01672738.

Abstract | Links

Direct Determination of One-Dimensional Interphase Structures Using Normalized Crystal Truncation Rod Analysis

Tomoya Kawaguchi, Yihua Liu, Anthony Reiter, Christian Cammarota, Michael S. Pierce, Hoydoo You

Direct Determination of One-Dimensional Interphase Structures Using Normalized Crystal Truncation Rod Analysis Journal Article

J. Appl. Crystallogr., 51 , pp. 1–6, 2018.

Abstract | Links

Structure Analyses of Fe-Substituted Li2S-Based Positive Electrode Materials for Li-S Batteries

Tomonari Takeuchi, Hiroyuki Kageyama, Noboru Taguchi, Koji Nakanishi, Tomoya Kawaguchi, Koji Ohara, Katsutoshi Fukuda, Atsushi Sakuda, Toshiaki Ohta, Toshiharu Fukunaga, Hikari Sakaebe, Hironori Kobayashi, Eiichiro Matsubara

Structure Analyses of Fe-Substituted Li2S-Based Positive Electrode Materials for Li-S Batteries Journal Article

Solid State Ionics, 320 (September 2017), pp. 387–391, 2018, ISSN: 01672738.

Abstract | Links

Layering and Ordering in Electrochemical Double Layers

Yihua Liu, Tomoya Kawaguchi, Michael S Pierce, Vladimir Komanicky, Hoydoo You

Layering and Ordering in Electrochemical Double Layers Journal Article

J. Phys. Chem. Lett., 9 , pp. 1265–1271, 2018, ISSN: 1948-7185.

Abstract | Links


Continue reading “Publication”

News&Articles

Complex Refractive Index

Generally, optics based on the electromagnetics is described with the refractive index, while such index does not barely appear in X-ray diffraction (XRD) from the kinematical approach, presumably because of the different historical background; however, it is of great importance to see their relationship to understand the diffraction anomalous fine structure (DAFS) method.
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Resonant Scattering

The atomic form factor is a Fourier transform of the electron distribution in an atom; therefore, it is a real number and independent of photon energy. In contrast, there exists an absorption edge and a fine structure in an absorption spectrum in the x-ray region. Thus, the absorption term should be included into the scattering length as an imaginary part, which is proportional to the absorption cross-section, by assuming a more elaborated model rather than that of a cloud of free electrons.
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Calculation of a structure factor

A structure factor is calculated by summing up scattering factors of each atom with multiplying the phases at each atomic position in a unit cell. It is a facile approach to calculate the structure factor; however, the calculation becomes complicated when the unit cell includes the large number of atoms. Thus, the calculation of the structure factor should be carried out based on the crystallographic site in space group, which is more versatile and convenient.
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Career

Assistant professor
Institute for Materials Research, Tohoku University, Japan,  2018-
Structure-Controlled Functional Materials Laboratory (prof. Tetsu Ichitsubo)

Previously..

Resident associate
Materials Science Division, Argonne National Laboratory, U.S.A., 2017-2019
Synchrotron Studies of Materials Group (supervisor: Hoydoo You)

JSPS overseas research fellow
Japan Society for Promotion of Science (JSPS), Japan, 2017-2019

Research assistant professor
Technical Director (Synchrotron Radiation Study Group) of RISING and RISING2 projects

Office of Society Academia Collaboration for Innovation, Kyoto University, Japan, 2015-2017

JSPS research fellow (DC2), JSPS, Japan, 2013 – 2015

Background

Education

  • Ph.D., Materials Science, Kyoto University, Kyoto, Japan, 2015
  • M.S., Material Science, Kyoto University, Kyoto, Japan, 2012
  • B.S., Engineering Science, Kyoto University, Kyoto, Japan, 2010
  • Science and Mathematics Course, Otemae High School, Osaka, Japan, 2006
  • TOEIC score: 925/990 as of 2019

Awards and Honors

  • Encouraging award, the Japanese Society for Synchrotron Radiation Research (JSSRR), 2016
  • Best student presentation award, annual meeting of JSSRR, 2015
  • Best student presentation award, annual meeting of JSSRR, 2014
  • Best student presentation award, annual meeting of JSSRR, 2013
  • (more…)

Research Experience

Argonne National Laboratory

Structural analysis of the electrochemical double layer using crystal truncation rod (CTR) analysis. Direct determination of the surface structure from CTR. Bragg coherent diffraction imaging of the internal composition of the alloy catalysis particles, Materials Science Division, Argonne National Laboratory, 2017 – 2019

(more…)