Oxide-ion diffusion in brownmillerite-type Ca2AlMnO5+δ from first-principles calculations
Oxide-ion diffusion in brownmillerite-type Ca2AlMnO5+δ from first-principles calculations
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基于第一性原理计算的褐针石型 Ca2AlMnO5+δ 中的氧离子扩散
DOI：
10.1039/d1cp05174a
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hiroki Moriwake and Isao Tanaka
中科院分区：
文献类型：
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作者：
Ushio Matsumoto;Akihide Kuwabara;Craig A. J. Fisher;Hiroki Moriwake and Isao Tanaka
使用第一原理计算系统地研究了褐针石氧化物 Ca2AlMnO5 和 Ca2AlMnO5.5 中的氧离子扩散途径。这些结构通过氧化和还原可逆地相互转化。我们使用微移弹性带法检查了 Ca2AlMnO5 和 Ca2AlMnO5.5 中的氧化物离子迁移。在还原结构 (Ca2AlMnO5) 中，通过空位通道的氧化物离子迁移被发现具有最低的迁移能垒，为 0.58 eV。垂直于空位沟道的第二低能量路径的迁移能垒为 0.98 eV。在氧化结构(Ca2AlMnO5.5)中，AlO6层内的氧化物离子迁移在[100]和[001]方向上的迁移能垒分别为0.55 eV和0.56 eV。垂直于 AlO6 层的氧化物离子迁移具有 1.33 eV 的迁移能垒，表明即使在高温下，氧化物离子在 [010] 方向上的扩散也很困难。这些结果表明还原相中的扩散主要是一维的，而氧化相中的扩散是二维的。
Oxide-ion diffusion pathways in brownmillerite oxides Ca2AlMnO5 and Ca2AlMnO5.5 are systematically investigated using first-principles calculations. These structures reversibly transform into each other by oxidation and reduction. We examine oxide-ion migration in Ca2AlMnO5 and Ca2AlMnO5.5 using the nudged elastic band method. In the reduced structure (Ca2AlMnO5), oxide-ion migration through a vacancy channel is found to have the lowest migration energy barrier, at 0.58 eV. The migration energy barrier of the second-lowest energy path, perpendicular to the vacancy channel, is found to be 0.98 eV. In the oxidized structure (Ca2AlMnO5.5), oxide-ion migration within AlO6 layers has migration energy barriers of 0.55 eV and 0.56 eV in the [100] and [001] directions, respectively. Oxide-ion migration perpendicular to the AlO6 layer has a migration energy barrier of 1.33 eV, suggesting that oxide-ion diffusion in the [010] direction is difficult even at elevated temperature. These results indicate that diffusion in the reduced phase is predominantly one-dimensional whereas it is two-dimensional in the oxidized phase.