Researcher Information

KOBAYASHI Hiroaki

Associate Professor

Development of next-generation batteries

Department of Chemistry, Inorganic and Analytical Chemistry

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Theme

Investigation of ionics of metastable materials, porous nanomaterials, and artificial interfaces

FieldMaterials chemisty, Electrochemistry, Inorganic chemistry
KeywordNext generation batteries, Porous nanomaterials, Metastable materials

Introduction of Research

Lithium-ion batteries are widespread not only in mobile devices but also in large energy storage systems. To meet the increasing demand of high-energy, low cost, and high safety, development of next generation batteries is indispensable. However, most of materials for the next generation batteries have low electric/ionic conductivity, hence novel materials and their synthesis procedures are requied. Our group focuses on materials chemistry for next generation batteries such as high capacity lithium-ion batteries, high-voltage solid-state batteries, and magnesium rechargeable batteries. Recently, we have developed metastable materials for fast ion conduction in solids and realizing new redox mechanisms, porous nanomaterials for fast ion conduction in the entire electrodes, and artificial interfaces for controlling ion mobility at high voltages.

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Metastable, ultrasmall nanoparticles obtained by nonequilibrium synthesis.
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Recent trends in high-capacity lithium-ion battery cathodes and high-capacity metastable antifluorite-type lithium-iron oxides.
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Improvement of magnesium ion insertion depth in solids using metastable, ultraporous, and ultrasmall cathode materials.

Representative Achievements

Toward Cost-Effective High-Energy Lithium-Ion Battery Cathodes: Covalent Bond Formation Empowers Solid-State Oxygen Redox in Antifluorite-Type Lithium-Rich Iron Oxide
H. Kobayashi,* Y. Nakamura, Y. Yokoyama, I. Honma, M. Nakayama
ACS Mater. Lett. 6, 2072-2076 (2024)
Ultraporous, Ultrasmall MgMn2O4 Spinel Cathode for a Room-Temperature Magnesium Rechargeable Battery
H. Kobayashi,* Y. Fukumi, H. Watanabe, R. Iimura, N. Nishimura, T. Mandai, Y. Tominaga, M. Nakayama, T. Ichitsubo, I. Honma, H. Imai*
ACS Nano 17, 3135-3142 (2023)
Metastable Cubic Structure Exceeds Capacity Limit of Antifluorite Li5FeO4 Cathode Using Small Polarized Oxygen Redox
H. Kobayashi,* Y. Nakamura, M. Nakayama, S. Kodaki, R. Matsuo, I. Honma
Adv. Energy Mater. 13, 2203441 (2023)
Are Redox‐Active Organic Small Molecules Applicable for High‐Voltage (>4 V) Lithium‐Ion Battery Cathodes?
Y. Katsuyama, H. Kobayashi,* K. Iwase, Y. Gambe, I. Honma*
Adv. Sci. 9, 2200187 (2022)
Research Press Release: A 4 V-class Metal-free Organic Lithium-ion Battery Gets Closer to Reality
Electrical Conductivity-Relay between Organic Charge-Transfer and Radical Salts toward Conductive Additive-Free Rechargeable Battery
Y. Fujihara, H. Kobayashi,* S. Takaishi, T. Tomai, M. Yamashita, I. Honma
ACS Appl. Mater. Interfaces 12, 25748-25755 (2020)

Related industries

Chemical industry, Materials industry, Energy industry, Automotive industry, Catalyst industry
Academic degreeDoctor of Engineering
Self Introduction

My hometown is Gumma. I went north from Kanto (Gumma and Tokyo), via Tohoku (Sendai), to reach Hokkaido (Sapporo). I have been involved in various materials research; catalysts at undergraduate, magnetic materials in my master's degree, and batteries in my Ph. D. Now I develop novel materials using my broad background. My hobbies are cooking and black tea.

Academic background2012 B. S., Faculty of Engineering, The University of Tokyo
2014 M. S., Graduate School of Arts and Sciences, The University of Tokyo
2017 Ph.D., Graduate School of Engineering, The University of Tokyo
2017 Assistant Professor, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
2022 Senior Assistant Professor, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
2023- Associate Professor, Faculty of Science, Hokkaido University
Affiliated academic societyThe Electrochemical Society of Japan, The Ceramic Society of Japan, The Solid State Ionics Society of Japan, The Chemical Society of Japan
ProjectJST Green Technologies of Excellence (GteX)
NEDO Intensive Support Program for Young Promising Researchers
Room addressScience Building 6, Room 6-4-06

Department of Chemistry, Inorganic and Analytical Chemistry

KOBAYASHI Hiroaki

Associate Professor

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Please briefly introduce us to the big project you have been tackling.

In the Green Technologies of Excellence (GteX) project organized by JST, we focus on a rechargeable battery using magnesium metal. Compared with commercialized batteries, such as Lead-acid and Li-ion batteries, the magnesium rechargeable battery can deliver high energy and cost-effectiveness. However, a critical issue is the compatibility of electrodes (cathodes and anodes) and electrolytes; facile materials and electrode designs are essential for the utilization of the rechargeable magnesium battery. We develop novel nano-structured cathode materials that can operate even at room temperature.

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What made you decide to become a researcher?

My hometown has a Children’s Science Museum commemorating astronaut Chiaki Mukai; I had many opportunities to experience science from an early age. During my undergraduate/graduate studies, I experienced several research groups and fields, and I became more interested in materials science.

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Please tell us about yourself; things you are good at, your favorites, hobbies, and daily routines.

My hobbies are cooking and black tea. On weekends, I often cook galette complète and pancakes, and make stewed tea. In Hokkaido, there is a famous Japanese black tea brand; I enjoy fresh Darjeeling tea.