Development of hydride ion conductor using surface and/or grain boundaries

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K18957
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Kumamoto University
• Principal Investigator: Ida Shintaro 熊本大学, 産業ナノマテリアル研究所, 教授 (70404324)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: ヒドリド / ナノシート / 同位体センサー

Outline of Final Research Achievements

Rhodium-doped titanium oxide layer compounds was synthesized as a hydride ion conductor in which the surface and grain boundaries were involved. We investigated whether the hydride species adsorbed on the rhodium-doped site exhibited surface hydride conduction. The conduction characteristics were evaluated in hydrogen or deuterium. The current-voltage characteristics and impedance characteristics changed when the H2 gas was changed to D2 gas, indicating that the ionic species involved in hydrogen are conducting. However, the conductivity was higher in the atmosphere in deuterium, which has a heavier mass, compared to the atmosphere in H2. These results indicated that new hydride conduction different from the normal hydride conduction mechanism may occur in the rhodium-doped titanium oxide layered body.

Free Research Field

無機材料化学

Academic Significance and Societal Importance of the Research Achievements

水素原子に1つの電子が付加したヒドリドは、その酸化還元電位が水素標準電極に対して－2.25Ｖとかなり卑な電位を持つため、単独のヒドリドと酸素で燃料電池が構築できれば、従来の水素燃料電池よりも大きなの起電力が得られる可能性がある。しかしながら、この材料は空気中で不安定であり、電池や燃料電池応用にはさらなる開発が必要であるとされている。また、ヒドリド伝導を示す材料は限られており、新しい設計コンセプトをもった材料開発が求められていた。本研究成果は、表面・粒界という切り口でヒドリドイオン伝導体を提案し、従来にはない伝導機構のヒドリドイオン伝導を示す可能性がある材料を創製できたことは学術的価値は高い。