In situ and Operando Tracking of Microstructure and Volume Evolution of Silicon Electrodes by using Synchrotron X-ray Imaging
In situ and Operando Tracking of Microstructure and Volume Evolution of Silicon Electrodes by using Synchrotron X-ray Imaging
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DOI：
10.1002/cssc.201801969
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发表时间：
2019-01-10
期刊：
影响因子：
8.4
通讯作者：
Manke, Ingo
中科院分区：
文献类型：
--
作者：
Dong, Kang;Markoetter, Henning;Manke, Ingo
在锂离子电池循环过程中，利用operando同步辐射x射线镜观察了硅电极的内部微观结构。发现硅颗粒在锂化和衰减过程中会发生尺寸变化，这种变化可以被量化。研究发现，颗粒的体积变化不仅与其初始尺寸有关，而且在很大程度上取决于破裂颗粒内部周围电导网络和内部界面化学环境（如电解质迁移、固-电解质界面扩展）的变化。此外，还发现了一种膨胀延长现象，即即使在切换电池电流方向后，一些颗粒仍在继续膨胀，并且预期会收缩，这可以通过假设颗粒核心和外区域的膨胀特性不同来解释。该研究为锂化和衰减过程中硅颗粒内部的过程提供了新的基本见解，也展示了operando同步加速器x射线成像研究电池材料降解机制的独特可能性。
The internal microstructure of a silicon electrode in a lithium ion battery was visualized by operando synchrotron X-ray radioscopy during battery cycling. The silicon particles were found to change their sizes upon lithiation and delithiation and the changes could be quantified. It was found that volume change of a particle is related to its initial size and is also largely determined by the changing surrounding electron-conductive network and internal interface chemical environment (e.g., electrolyte migration, solid-electrolyte interphase propagation) within fractured particles. Moreover, an expansion prolongation phenomenon was discovered whereby some particles continue expanding even after switching the battery current direction and shrinkage would be expected, which is explained by assuming different expansion characteristics of particle cores and outer regions. The study provides new basic insights into processes inside Si particles during lithiation and delithiation and also demonstrates the unique possibilities of operando synchrotron X-ray imaging for studying degradation mechanisms in battery materials.