在无序岩盐阴极中的结构进化
Tianyu Li1,2, Tullio S Geraci3,4, Krishna Prasad Koirala5,6
1Materials Department, University of California Santa Barbara, Santa Barbara 93106, California, United States.
Journal of the American Chemical Society
|August 22, 2024
概括
在加热时,过量的乱岩盐氧化物 (DRX) 转化为有益的"δ阶段",增强离子电池的容量. 这种由离子迁移驱动的结构进化在富含的材料中更为明显.
科学领域:
- 材料科学
- 电化学
- 固态化学
背景情况:
- 过量无序岩盐氧化物 (DRX) 是具有高理论容量的离子电池的成本效益高的阴极材料.
- 富含的DRX (Li1+MnM1-O2,y ≥0.5) 在循环过程中显示出容量增加,这与与螺旋状域形成的"δ阶段"有关.
研究的目的:
- 系统地研究基于Mn的DRX在各种脱状态下加热后的结构演变.
- 了解电池循环过程中的结构重组以及δ相形成的机制.
主要方法:
- 同步X射线和中子衍射分析"δ阶段"的结构.
- 在现场加热X射线衍射 (XRD) 实验.
- 热化学研究
主要成果:
- 所有研究的DRX结构在加热后放松到"δ阶段",从而提高容量.
- 在DRX结构中选择性和的迁移导致观察到的结构重组.
- 富含Mn和缺乏Mn的DRX都可以在脱后放松到"δ阶段",但具有不同的域结构.
结论:
- "δ阶段"形成是过量Mn基DRX容量增强的一个关键机制.
- 富含的DRX具有较大的热力学驱动力和较低的激活能量,用于"δ相"放松,这解释了其在电池循环期间的普遍性.
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