Functional development by trying a defect-structure stabilization utilizing high-pressure environments

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K19186
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials chemistry, Energy-related chemistry, and related fields
• Research Institution: National Institute for Materials Science
• Principal Investigator: MIYAKAWA Masashi 国立研究開発法人物質・材料研究機構, 機能性材料研究拠点, 主任研究員 (40552667)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 高圧プロセス / 高温電気伝導度 / イオン伝導体

Outline of Final Research Achievements

Exploration of a new compound with perovskite-type structure containing abundant oxygen deficiency was carried out in tungsten complex oxides by using a high-pressure process. As a result, materials with double perovskite-type, and high-pressure phase with new structure were found in this study. From the results of the temperature dependences of the total electrical conductivities, conductivities in the observed materials were increased with increasing the lattice constants. Moreover, in the lower temperature region (≦500℃), there were substances which exhibited the same level of conductivity as YSZ.

Free Research Field

高圧合成

Academic Significance and Societal Importance of the Research Achievements

高い酸素イオン伝導のためには、酸素空孔を導入し、酸素イオンが移れる空サイトを用意する必要があるが、陰イオン数の減少は、必然、電荷中性条件を満たすために陽イオンの価数を減らすことに繋がり、同時に構造の低配位化を促し易い。本研究成果では、高配位化を促す高圧合成プロセスを利用することで、元の結晶構造を維持しつつ、置換ドーピングによる酸素欠損が導入できると、物質探索におけるアプローチの1つとして、高圧環境を利用したアプローチが有用である、と示せたことに学術的意義があると考える。