两相形态限制了在TiO(2)(anatase中的扩散):一个 (7)Li MAS NMR研究
M Wagemaker1, R van de Krol, A P Kentgens
1Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands.
Journal of the American Chemical Society
|November 15, 2001
概括
在二氧化中的离子流动性使用7Li固态NMR进行了研究. 研究人员发现,相位边界显著影响了整体扩散率,这表明电子效应可能促进了移动性.
科学领域:
- 固态无机化学 固态无机化学
- 材料科学是一种材料科学.
- 电化学 电化学 电化学
背景情况:
- 二氧化 (TiO2) 是一个有前途的材料用于储能应用.
- 了解离子扩散对于优化电池性能至关重要.
- 在插入过程中相位分离会影响材料性能.
研究的目的:
- 为了研究TiO2和Li的局部环境和离子流动性{0.6) TiO2.2.
- 为了阐明控制扩散率的因素.
- 探索电子结构和离子流动性之间的关系.
主要方法:
- 7Li魔力角度旋转固态核磁共振 (NMR) 光谱.
- 分析相位分离和晶体结构变化.
- 温度依赖的NMR测量以确定激活能量.
主要成果:
- 阶段分离发生,形成丰富的0.6) TiO2和贫 TiO2阶段.
- 离子在两个阶段都表现出低激活能的跳跃 (anatase中的0.2 eV,titanate中的0.09 eV).
- 宏观扩散速度较慢,激活能量较高 (~0.5 eV),归因于相位边界扩散.
结论:
- 阶段边界扩散是整体间隔的速度限制阶段.
- 在更高的温度下,电子变化与的流动性增加有关.
- 固态NMR提供了对基于TiO2的材料的离子动力学和结构性质关系的见解.
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