Understanding the difference in bulk modulus between Y-doped SrCeO3 and Y-doped SrZrO3 by ultrasonic transmission method and density functional theory

Takaya Fujisaki, Keisuke Hinata, Fumitada Iguchi, Nikolay Dimov, Aleksandar Tsekov Staykov, Hiroshige Matsumoto

研究成果: ジャーナルへの寄稿学術誌査読

抄録

Proton-conducting oxides are promising for applications in solid oxide fuel cells and steam electrolysis at intermediate temperatures (400–600 °C). The hydration reaction requires oxide ion vacancies and the protonic conductive species originate from this reaction. Increasing the proton concentration leads to higher proton conductivity but also expands the lattice volume, known as chemical expansion, which may lead to the mechanical failure of the oxide. Thus, it is important to clarify the factors that decrease the chemical expansion. A previous study suggested that chemical expansion could be suppressed by a large bulk modulus. Although this was only a qualitative argument, our study quantitatively clarifies the effect of the bulk modulus experimentally and theoretically. To examine the difference between Ce and Zr, which are typical elements in proton-conducting oxides, 6.25 mol% Y-doped SrZrO3 and SrCeO3 were prepared, and their bulk moduli were quantitatively evaluated. Y-doped SrZrO3 had a larger bulk modulus than Y-doped SrCeO3. Our results support the previous finding that proton-conducting oxides with large bulk modulus suppress chemical expansion. In addition, our theoretical calculations of the force constants showed that the difference in bulk modulus was caused by the Zr-O bonds being more rigid than the Ce-O bonds. Our results should provide useful guidelines for suppressing chemical expansion in proton-conducting oxides.

本文言語英語
論文番号101616
ジャーナルMaterialia
26
DOI
出版ステータス出版済み - 12月 2022

!!!All Science Journal Classification (ASJC) codes

  • 材料科学一般

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