Theoretical investigation on defect structure and ion dynamics in solid electrolytes

• 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
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
• Keywords: 第一原理計算 / プロトン伝導体 / 点欠陥 / 拡散 / 固体イオニクス / イオン伝導体 / プロトン / 酸化物 / 分子動力学計算 / 酸化物イオン / 固体酸化物燃料電池 / 固溶体

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.

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。

Research Products

• [Presentation] First principles calculation of charge-carrier and defect concentration of R2O3-doped BaZrO3 (2018)
  • Author(s): A. Kuwabara, T. Ogawa, C. A. J. Fisher, H. Moriwake
  • Organizer: 10th Kyoto International Forum for Environment and Energy
  • Int'l Joint Research / Invited
• [Presentation] アクセプター添加BaZrO3におけるドーパントおよび酸素欠損の固溶状態に関する第一原理計算 (2017)
  • Author(s): 桑原彰秀, 志賀元紀, クレイグ・フィッシャー, 森分博紀
  • Organizer: 日本金属学会2017年秋季講演大会
• [Presentation] First-Principles Calculations of Complex Defects in Mixed-Anion Perovskites (2017)
  • Author(s): Akihide Kuwabara, Kazuki Shitara, Craig A. J. Fisher
  • Organizer: The 6th Toyota RIKEN International Workshop
  • Int'l Joint Research
• [Presentation] 第一原理計算による複合アニオン化合物の特異な配位環境の解明 (2017)
  • Author(s): 桑原彰秀, 設樂一希, 山本隆文, 陰山洋
  • Organizer: 第11回物性科学領域横断研究会
  • Invited
• [Presentation] First Principles Calculations of Solid Solution States in Y-doped BaZrO3 (2016)
  • Author(s): Akihide Kuwabara, Motoki Shiga, Craig A. J. Fisher, Hiroki Moriwake
  • Organizer: 18th International Conference on Soid State Proton Conductors
  • Place of Presentation: Soria Moria, Oslo, Norway
  • Year and Date: 2016-09-18
  • Int'l Joint Research
• [Presentation] FIRST PRINCIPLES CALCULATIONS OF DEFECT CLUSTERING IN ACCEPTOR-DOPED BaZrO3 (2016)
  • Author(s): Akihide Kuwabara, Craig A. J. Fisher, Yuji Okuyama, Yoshihiro Yamazaki
  • Organizer: Nonstoichiometric Compounds VI
  • Place of Presentation: LaFonda on the Plaza, Santa Fe, USA
  • Year and Date: 2016-09-04
  • Int'l Joint Research / Invited