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Materials Molecular Science Kobayashi Group

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Location: Myoudaiji, South Laboratory Bldg. Room303
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Solid State Ionics, Oxyhydride, Battery

Materials Science for Creation of Novel Electrochemical Devices

Chemical energy conversion/storage using electrochemical devices such as fuel cells and batteries will become increasingly important for future sustainable societies. Recently, many research for advanced electrochemical devices beyond Li secondary batteries and fuel cells have been actively carried out worldwide. A breakthrough of core materials used as electrodes and electrolytes is required to open up the frontier in the electrochemical devices. An injection of new ion conduction phenomenon is one of the dominant candidates for the creation of novel battery systems. We focus on hydride ions (H) as a candidate of charge carriers for energy devices. In this context, we aim to synthesize new materials possessing hydride ion (H) conductivity, and to develop a novel battery system utilizing both the H conduction phenomenon and the H/H2 redox reaction.


Crystal structures of La2-x-ySrx+yLiH1-x+yO3-y (x = 0, y = 0, 1, 2). The coordination environment around lithium ions continuously changes with a change in the O/H ratio. The four axial sites of the Li-anion octahedra (anion sites in Li-anion planes perpendicular s-axis) prefer to be occupied by H.

Selected Publications

  1. F. Takeiri, A. Watanabe, A. Kuwabara, H. Nawaz, N. Ayu, M. Yonemura, R. Kanno and G. Kobayashi*, "Ba2ScHO3: H Conductive Layered Oxyhydride with H Site Selectivity," Inorg. Chem. 58, 4431-4436 (2019).
  2. N. Matsui, G. Kobayashi*, K. Suzuki, A. Watanabe, A. Kubota, Y. Iwasaki, M. Yonemura, M. Hirayama, R. Kanno*, "Ambient pressure synthesis of La2LiHO3 as a solid electrolyte for a hydrogen electrochemical cell," J. Am. Ceram. Soc.102, 3228-3235 (2019).
  3. A. Watanabe, G. Kobayashi*, N, Matsui, M. Yonemura, A. Kubota, K. Suzuki, M. Hirayama, R. Kanno, "Ambient pressure synthesis and H conductivity of LaSrLiH2O2," Electrochem. 85, 88-92 (2017).

  4. G. Kobayashi*, Y. Hinuma, S. Matsuoka, A. Watanabe, I. Muhammad, M. Hirayama, M. Yonemura, T. Kamiyama, I. Tanaka and R. Kanno*, “Pure H Conduction in Oxyhydrides,” Science 351, 1314-1317 (2016).

  5. G. Kobayashi*, Y. Irii, F. Matsumoto, A. Ito, Y. Ohsawa, S. Yamamoto, Y. Cui, J.-Y. Son and Y. Sato, “Improving Cycling Performance of  Li[Li0.2Ni0.18Co0.03Mn0.58]O2 through Combination of Al2O3-based Surface Modification and Stepwise Pre-cycling,” J. Power Sources 303, 250-256 (2016).