在操作中的X射线吸收聚氧甲分子集群电池的细结构研究:聚氧甲作为电子海绵
Heng Wang1, Shun Hamanaka, Yoshio Nishimoto
1Department of Chemistry and Research Center for Materials Science (RCMS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Journal of the American Chemical Society
|February 23, 2012
概括
使用聚氧甲酸盐的分子集群电池实现了高容量. 一个超缩小状态存储24个电子,解释了这些可充电电池的大容量.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 无机化学 无机化学
背景情况:
- 可充电分子集群电池 (MCB) 为高容量储能提供了潜力.
- 聚氧甲酸盐 (POM) 是多功能无机集群,具有可调节的氧化还原特性.
研究的目的:
- 研究Keggin型POM在MCB中的电化学行为和结构变化.
- 阐明基于POM的电池中观察到的高容量背后的机制.
主要方法:
- 在运行中Mo K边缘X射线吸收细结构 (XAFS) 测量.
- 对X射线吸收近边缘结构 (XANES) 和扩展的X射线吸收细结构 (EXAFS) 的分析.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 使用[PMo{12) O{40) ]{3-) 的POM-MCB具有大约270Ah/kg的大容量.
- XANES证实了所有12个Mo(6+) 离子的降解为Mo(4+),形成一个24电子超降解状态,[PMo(12) O(40) ](27-).
- EXAFS 和 DFT 揭示了超缩小状态下Mo(4+) 金属与金属结合的三角形的形成.
结论:
- 在超减小的POM状态下,24电子的存储是MCBs高容量的原因.
- 摩4+) 三角形的形成是由超缩小POM结构中的多余电子驱动的.
- 这项研究表明POMs作为可充电电池的高性能阴极材料的潜力.
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