Research Summary

Selected Publications

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

• 1. Yaguchi, H., Takeiri, F., Komurasaki, S., Kobayashi, T., Saito, T., Hosokawa, S., Mori, K., Kobayashi, G.:
  "Palmierite‐Type Oxyhydride Ba₃V₂H_0.5O_7.5 With Vanadium Charge Ordering"
  Small Structures, 7, e202500630 (2026).
• 2. Takeiri, F., Oshime, N., Muhammady, S., Uchimura, T., Yaguchi, H., Haruyama, J., Machida, A., Watanuki, T., Saito, T., Mori, K., Ohwada, K., Kitano, M., Kobayashi, G.:
  "Mechanochemical Synthesis of H^– Materials: Hydrogen-Rich Perovskite Oxyhydrides with Lattice Strain as an Ammonia Synthesis Catalyst"
  J. Am. Chem. Soc., 147, 24482-24490 (2025).
• 3. 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).
• 4. 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).
• 5. 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).
• 6. *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).
• 7. *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).
• 8. *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).
• 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

• 

  Aug. 26, 2025
  More hydrogen, more ammonia, more fertilizer, all using less energy

• 

  Dec. 23, 2023
  New material allows for better hydrogen-based batteries and fuel cells

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