通过使用高分辨率的MAS NMR技术来解决离子导体BaSnF(4) 中子子网的不同动态
Santanu Chaudhuri1, Francis Wang, Clare P Grey
1Department of Chemistry, State University of New York, Stony Brook, NY 11794-3400, USA.
Journal of the American Chemical Society
|September 26, 2002
概括
离子导体BaSnF(4) 呈现出两个不同的子线. 在Ba和Sn层之间移动的化物离子促进了快速的2D导电性,而较慢的3D导电性需要层间跳跃.
科学领域:
- 固态化学 固态化学
- 材料科学是一种材料科学.
- 核磁共振光谱学 核磁共振光谱学
背景情况:
- BaSnF ((4) 属于MSnF ((4) 家族,以化物相关的离子导电性而闻名.
- 了解离子流动性对于开发先进的导电材料至关重要.
- 离子导体是电化学设备中的关键组件.
研究的目的:
- 用先进的NMR技术研究BaSnF(4) 中离子的动态.
- 为了阐明这种分层材料中离子导电性的机制.
- 为了将结构特征与观察到的离子移动性和导电性相关联.
主要方法:
- 固态核磁共振 (NMR) 谱学,特别是19F和119Sn MAS NMR.
- 可变温度实验用于研究广泛温度范围 (-150至250°C) 的离子动力学.
- 19F-119Sn交叉极化 (CP) 和二维交换NMR实验探测局部环境和离子交换.
主要成果:
- 确定了两个不同的子网格:在Ba2+层中的刚性子网格和在Ba/Sn层之间移动的子网格.
- 对于移动子网格,观察到极快的离子运动 (在-100°C时的相关时间<3 x 10^-5秒).
- 有证据表明,刚性和移动子网之间交换缓慢,并且在-150°C以下的运动几乎完全结.
结论:
- 结果支持在移动化物子网格内的快速二维异性导电性的模型.
- 三维导电性受到层间跳跃过程较慢的限制.
- 核磁共振谱学有效地区分和量化复杂的层结构如BaSnF的离子流动性.
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