Study on H- conductive materials for the development of novel ionics devices

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05497
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Inorganic industrial materials
• Research Institution: Institute for Molecular Science
• Principal Investigator: Kobayashi Genki 分子科学研究所, 協奏分子システム研究センター, 特任准教授 (30609847)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: ヒドリドイオン導電体 / 超イオン導電体 / 固体イオニクス

Outline of Final Research Achievements

Pure H- conduction was realized in the La2-x-ySrx+yLiH1-x+yO3-y system (LSLHO). The all-solid-state Ti/LSLHO/TiH2 cell exhibited a discharge reaction with hydrogen storage/desorption on the electrodes. The present success confirms not only the capability of LSLHO to act as a solid hydride electrolyte, but also the possibility of developing electrochemical solid devices based on H－ conduction.
We established the simple synthesis method at ambient pressure (AP) for LSLHO. An AP sample with low H- concentration exhibited a crystal structure and a conductivity similar to those observed for the HP sample. In contrast, Sr2LiH3O synthesized at AP has super lattice that is formed by ordering of H-/vacancies and H/O in the axial and apical anion sites, respectively. The H- conductivity of AP sample of Sr2LiH3O jumped around 648 K with disordering them, and showed high conductivity over 1 mS/cm.
We synthesized a H- super ionic conductor Ba2LiH3O possessing a conductivity over 10 mS/cm at 588 K

Free Research Field

無機固体化学、固体イオニクス、電気化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、ヒドリドイオン導電性の固体電解質として機能するLSLHOを開発し、それを用いた電気化学デバイス開発の可能性を示した。これは、固体イオニクスと電気化学の新たな研究対象であり、学術的意義は大きい。さらに、その後の物質開発を進展させ、中温域で超イオン導電性を示すBa2LiHO3の開発にも成功した。
将来的にヒドリドとプロトンの間の水素の電荷自由度を活用する電気化学反応を構築することができれば、エネルギー貯蔵・変換、物質変換に応用できる可能性があり、持続可能社会の実現に資する要素技術になり得る。