Mechanism of Ionic Conduction in Carbonate Apatite by First-principles Calculations

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K13998
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Osaka University
• Principal Investigator: Shitara Kazuki 大阪大学, 接合科学研究所, 助教 (40756805)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: ハイドロキシアパタイト / 炭酸アパタイト / 第一原理計算

Outline of Final Research Achievements

We investigated the defect structures and the ionic conduction mechanism in Na- and K-doped carbonate apatite by first-principles calculations. It was revealed that there is a vacancy at the oxygen site in phosphorous ion by substituting with carbonate ion. First-principles molecular dynamics was also performed from the initial structure based on the above defect structure, hydroxide ion was moved to the vacancy generated by carbonate ion. As a result, other hydroxide ions were widely distributed on the c-axis. It is suggested that the migration and broadening of the distribution of hydroxide ions contribute to ionic conduction in the carbonate apatite.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

本研究は従来報告されてきたような酸素過剰型ではなく，酸素欠損型のアパタイト構造イオン伝導体の可能性を第一原理計算により探った．炭酸アパタイト中のイオン伝導メカニズムを明らかにした本研究成果は，新たな伝導機構に基づくアパタイト型酸化物イオン伝導体の設計につながる．これは新規固体酸化物形燃料電池や酸素センサーの開発につながり，省エネルギー化や自然エネルギーの有効利用に大きく貢献できると考えられる．