1. Home
  2. Research
  3. Centers & Labs
  4. Chief Scientist Laboratories etc

Chief Scientist Laboratories Solid State Chemistry Laboratory

Chief Scientist: Genki Kobayashi (Ph.D.)

Research Summary


Effective utilization of renewable energy and a shift away from mass consumption of fossil fuels are essential for building a sustainable society, which requires new technologies that enable highly efficient energy and material conversion and high-density energy storage. Based on inorganic solid-state chemistry, we explore outstanding ionics materials, including electrodes and solid electrolytes with innovative functions. We are researching a wide range of topics, from elucidating the mechanisms of physical properties and functions to developing energy storage/conversion and material conversion devices based on new operating principles.

Main Research Fields

  • Chemistry

Related Research Fields

  • Engineering
  • Interdisciplinary Science & Engineering
  • Inorganic Materials Chemistry
  • Energy-related Chemistry
  • Inorganic Materials and properties


  • Solid State Ionics
  • Exploration for New Functional Materials
  • Energy Storage & Conversion
  • Material Conversion
  • Ceramics

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.

  • 1. Izumi, Y., Takeiri, F., Okamoto, K., Saito, T., Kamiyama, T., Kuwabara, A., Kobayashi, G.:
    "Electropositive Metal Doping into Lanthanum Hydride for H- Conducting Solid Electrolyte Use at Room Temperature”
    Advanced Energy Materials, 13, 2301993 (2023).
  • 2. Okamoto, K., Takeiri, F., Imai, Y., Yonemura, M., Saito, T., Ikeda, K., Otomo, T., Kamiyama, T., Kobayashi, G.:
    "Impact of Na Concentration on the Phase Transition Behavior and H- Conductivities in the Ba-Li-H-O Oxyhydride System”
    Advanced Science 10, 2203541 (2023).
  • 3. Okamoto, K., Takeiri, F., Imai, Y., Yonemura, M., Saito, T., Ikeda, K., Otomo, T., Kamiyama, T., Kobayashi, G.:
    "Stabilization of a high H-- conducting phase via K doping of Ba-Li oxyhydride"
    J. Materials Chem. A 10, 23023-23027 (2022).
  • 4. *Takeiri, F., Watanabe, A., Okamoto, K., Bresser, D., Lyonnard, S., Frick, B., Ali, A., Imai, Y., Nishimura, M., Yonemura, M., Saito, T., Ikeda, K., Otomo, T., Kamiyama, T., Kanno, R., Kobayashi, G.:
    "Hydride-Ion-Conducting K2NiF4-Type Ba-Li Oxyhydride Solid Electrolyte”
    Nature Materials 21, 325-330 (2022).
  • 5. *Uchimura, T., Takeiri, F., Okamoto, K., Saito, T., Kamiyama, T., Kobayashi, G.:
    "Direct Synthesis of Barium Titanium Oxyhydride for Use as a Hydrogen Permeable Electrode”
    J. Materials Chem. A 9, 20371-20374 (2021).
  • 6. *Nawaz, H., Takeiri, F., Kuwabara, A., Yonemura, M., Kobayashi, G.:
    "Synthesis and H- Conductivity of New Oxyhydride Ba2YHO3 with Anion-Ordered Rock-Salt Layers”
    Chem. Commun. 56, 10373-10376 (2020).
  • 7. *Takeiri, F., Watanabe, A., Kuwabara, A., Nawaz, H., Ayu, N., Yonemura, M., Kanno, R., Kobayashi, G.:
    "Ba2ScHO3: H- Conductive Layered Oxhydride with H- Site Selectivity”
    Inorg. Chem. 58, 4431-4436 (2019).
  • 8. *Watanabe, A., Kobayashi, G., Matsui, N., Yonemura, M., Kubota, A., Suzuki, K., Hirayama, M., Kanno, R.:
    "Ambient Pressure Synthesis and H- Conductivity of LaSrLiH2O2
    Electrochem. 85(2), 88-92 (2017).
  • 9. *Kobayashi, G., Hinumra, Y., Matsuoka, S., Watanabe, A., Iqbal, M., Hirayama, M., Yonemura, M., Kamiyama, T., Kanno, R.:
    "Pure H- Conduction in Oxyhydrides”
    Science 351, 1314-1317 (2016).
  • 10. *Kobayashi, G., Irii, Y., Matsumoto, F., Ito, A., Ohsawa, Y., Yamamoto, S., Cui, Y., Son, J.-Y., Sato, Y.:
    "Improving Cycling Performance of Li-Rich Layered Cathode Materials Through Combination of Al2O3-Based Surface Modification and Stepwise Pre-cycling”
    J. Power Sources 303, 250-256 (2016).

Recent Research Results

Lab Members

Principal investigator

Genki Kobayashi
Chief Scientist

Core members

Masuki Kawamoto
Senior Research Scientist
Jun Haruyama
Research Scientist
Hiroshi Yaguchi
Special Postdoctoral Researcher
Keiko Kusumoto
Student Trainee
Akihisa Inoue
Student Trainee
Masato Konuma
Student Trainee
Yu Machida
Student Trainee
Noriko Tanaka

Contact Information

N505 Chemistry and Materials Physics Building
2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Email: genki.kobayashi [at] riken.jp