Spatial Quantification of Microstructural Degradation during Fast Charge in 18650 Lithium-Ion Batteries through Operando X-ray Microtomography and Euclidean Distance Mapping
Spatial Quantification of Microstructural Degradation during Fast Charge in 18650 Lithium-Ion Batteries through Operando X-ray Microtomography and Euclidean Distance Mapping
复制标题
通过操作 X 射线显微断层扫描和欧几里德距离测绘对 18650 锂离子电池快速充电期间微观结构退化进行空间量化
DOI：
10.1021/acsaem.2c02397
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发表时间：
2022
影响因子：
6.4
通讯作者：
Nelson Weker, Johanna
中科院分区：
文献类型：
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作者：
Allen, Eva;Lim, Linda Y.;Xiao, Xianghui;Liu, Albert;Toney, Michael F.;Cabana, Jordi;Nelson Weker, Johanna
在1C以上的速度下快速充电会加速由局部温度升高和电荷不均匀传输引起的结构退化。在微米级，第一个损伤迹象是电极层不可逆转的膨胀。电极损伤通常涉及活性材料和导电粘结剂基质之间的空洞形成。这种演变的量化必须实时进行，因此必须是非破坏性的。我们报告了在快速充电循环下的圆柱形细胞的OPANDO X射线显微断层扫描。在之前的快速充电循环后，两个18650电池在循环过程中进行了测量，以跟踪电池寿命不同时间点的形态损伤。采用深度学习分割的方法对电极退化进行客观量化。利用欧氏距离映射，对电极膨胀和空洞进行了空间分辨。在充放电过程中，随着电极空隙的不可逆转增加，阳极层中高度可逆的膨胀趋势被量化。在靠近电流收集器的前10μm内，阳极空隙显示出明显的局部化，表明分层在进一步的循环中扩散。阴极膨胀的趋势与阳极相反，波动较大，阴极空隙总体减少。深入了解快速充电如何导致结构破坏，更好地为快速充电协议和电池化学的研究提供信息。
Fast charging at rates above 1C aggressively accelerates structural degradation induced by increases in local temperature and inhomogeneous transport of charge. At the micron scale, the first indication of damage is irreversible expansion of the electrode layers. Electrode damage often involves void formation between the active material and conductive binder matrix. Quantification of this evolution must be carried out in real time and, thus, nondestructively. We report operando X-ray microtomography of cylindrical cells under fast-charge cycling. Two 18650 batteries were measured during cycling after antecedent fast charging cycles to track morphological damage at different points of battery life. A method of deep learning segmentation was used to objectively quantify the electrode degradation. Using Euclidean distance mapping, electrode dilation and voids were spatially resolved. Highly reversible trends in dilation were quantified during charge/discharge in the anode layers with irreversible increases in electrode voids. Anode voids showed clear localization within the first 10 μm near the current collectors, indicating delamination that spread upon further cycling. The cathode dilation trended opposite to the anode with higher fluctuations and an overall decrease in cathode voids. Insight into how fast charging induces structural damage better informs research into fast-charge protocols and battery chemistries.