Theoretical investigation on defect structure and ion dynamics in solid electrolytes

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06739
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: Japan Fine Ceramics Center
• Principal Investigator: Kuwabara Akihide 一般財団法人ファインセラミックスセンター, その他部局等, 主任研究員 (30378799)
• Research Collaborator: Moriwake Hiroki ; Fisher Craig ; Shitara Kazuki
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 第一原理計算 / プロトン伝導体 / 点欠陥 / 拡散

Outline of Final Research Achievements

Acceptor-doped BaZrO3 is expected to be utilized as a solid electrolyte of a proton conductive solid oxide fuel cell. We need to further improve the proton conductivities of BaZrO3 for application. As one of the causes of the decrease in proton conductivity, there is an association phenomenon in which protons are captured near the acceptor dopants. In order to clarify the association state, first principles calculations are comprehensively executed for structural model groups in which configurations of dopants, oxide ion vacancies, and protons are systematically changed. The energies of association were evaluated by analysis of the relationship between configurations and energy states. Calculations for the high concentration solid solution model confirmed that it is possible to control the association energy by the configuration of the dopants.

Free Research Field

第一原理計算を用いた無機材料の物性解析

Academic Significance and Societal Importance of the Research Achievements

三体以上の欠陥を含んだ配置の異なる構造モデル群に対する網羅的な第一原理計算を実行することで、現実の固溶体で起こっている欠陥同士の相互作用を取り込んだエネルギー状態の定量評価を実施することができた。添加元素の固溶状態を変化させることで、会合の要因となるドーパント濃度が増大しても会合エネルギーが増大しない固溶状態が存在することが発見された。固溶状態を制御することでプロトンのトラップ現象を制御できる可能性が示されたことは、BaZrO3の材料設計において重要な成果である。