调节的异位氧化物离子导体CeNbO中的局部结构和扩散路径的相关性
Stevin S Pramana1, Tom Baikie, Tao An
1Department of Materials, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
Journal of the American Chemical Society
|January 16, 2016
概括
酸 (CeNbO4.25) 显示出快速的氧离子扩散,这对于能源设备至关重要. 它的复杂结构有助于异构离子的运输,主要是在层内进行运动,并且在层之间进行二次运动.
科学领域:
- 材料科学
- 固态化学
- 能量储存
背景情况:
- 酸 (CeNbO4.25) 是一个有前途的离子导体.
- 在中等温度下其快速氧离子扩散的机制尚不清楚.
- 材料的复杂模块化结构阻碍了详细的分析.
研究的目的:
- 阐明CeNbO4.25中的离子运输机制.
- 了解快速氧离子扩散的结构基础.
- 研究结构调节和氧气结合的作用.
主要方法:
- 通过X射线衍射来确定晶体结构.
- 对离子长距离螺旋排序的分析.
- 用于模拟离子迁移路径的分子动态模拟.
主要成果:
- 由于螺旋式的Ce3+/Ce4+排序,CeNbO4.25的单元细胞大约是原始相的12倍.
- 氧气的结合会诱导合作位移,形成NbO6之间的连接,并增加氧气的协调.
- 分子动力学揭示了异性离子迁移,主要是在xz平面内.
结论:
- 在CeNbO4.25中,异性氧化离子扩散主要是层内.
- 当层内通道被阻塞时,氧气在层之间存在较低的能量通道.
- 这种理解是优化酸盐在能源设备中的关键.
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