研究阳极中的储存机制:结合对分布函数分析,密度函数理论和固态NMR方法
Joshua M Stratford1, Martin Mayo2, Phoebe K Allan1,3,4
1Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K.
Journal of the American Chemical Society
|May 5, 2017
概括
研究人员研究了离子电池的阳极中的合金机制. 他们发现了新的-锡结构和中间体,揭示了在插入过程中如何转化以提高电池性能.
科学领域:
- 材料科学
- 电化学
- 计算化学
背景情况:
- 离子电池 (SIB) 是离子电池的有希望的替代品,因为它们含有大量的.
- 锡基材料正在作为SIB的高容量阳极进行研究,但它们的合金机制尚未完全理解.
- 了解化过程中的结构演变对于设计高效的锡阳极至关重要.
研究的目的:
- 在离子电池中插入时阐明锡阳极的合金机制.
- 识别和描述在阳极的电化学循环过程中形成的中间晶体和无形相.
- 将理论预测与实验观测联系起来,以全面了解-锡结构.
主要方法:
- 结合理论 (ab initio随机结构搜索,高通量选) 和实验 (操作对分布函数分析,X射线衍射,Na和Sn固态核磁共振) 方法.
- 使用物种交换方法来探索-锡结构.
- 采用反向的蒙特卡洛精细化对初始分子动力学模型进行无形相分析.
主要成果:
- 之前未知的晶体和无形-锡中间体的拟议结构.
- 确定了最初形成的分层NaSn3阶段,其次是热力学稳定的NaSn2.
- 具有链状锡连接性的无形Na1.2Sn阶段,随后在Na5-xSn2结构中形成Sn-Sn.
- 确定最后的Na15Sn4阶段可以容纳额外的作为非静态度化合物 (Na15+xSn4).
结论:
- 这项研究提供了SIB阳极的合金机制的详细理解.
- 鉴定到的中间结构及其形成途径为优化基阳极材料提供了洞察力.
- 这些发现有助于开发具有更高性能的下一代离子电池.
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