Control of oxide-ion conduction and exploring interface ionics of transition-metal oxide thin films

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K19177
• 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: Kyoto University
• Principal Investigator: Shimakawa Yuichi 京都大学, 化学研究所, 教授 (20372550)
• Research Collaborator: KAN Daisuke ; KURATA Hiroki
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: 遷移金属酸化物 / 酸素イオン伝導 / 薄膜

Outline of Final Research Achievements

The present study has mainly focused on oxide-ion conducting oxides. We have made a heterostructure consisting of SrFeO2.5 and DyScO3. The oxygen-vacancy-disordered structure is stabilized at the interfacial region. This implies that melting of oxygen vacancy order is induced at the interface at ambient temperatures. The results show that the oxygen coordination environments in the heterostructure can be controlled and highlight the possibility of stabilizing at the interface a structure.
Our conducting-AFM observations on SrFeO2.5 reveal that brownmillerite-to-perovskite structural changes due to air-annealing and oxidizing the film enhances conduction only in the terraces near the outer step edges. This indicates that the oxidation proceeds by preferential incorporation of oxygen in the local regions of the terraces and diffusion of that oxygen into the film. The results highlight the significance of nanoscale oxygen dynamics and associated redox reactions in SrFeO2.5 films.

Free Research Field

固体化学

Academic Significance and Societal Importance of the Research Achievements

資源・エネルギー・環境といった分野で多くの問題が顕在化してきているが、これらの問題の解決に向けてイオン伝導を中心とする基礎材料研究を展開してきた。得られた知見は、主として基礎的なイオニクスを中心として新しい学術・技術分野に発展の礎となるものであるが、将来の新しい燃料電池技術などの開発に向けた基盤技術となるものでもある。高効率でかつ低温で動作する固体酸化物燃料電池の開発にもつながる結果であり、エネルギー・環境問題の解決のみならず、快適で便利な社会の基盤技術となるものである。