Emerging chemical heterogeneities in a commercial 18650 Li-ion battery during early cycling
Emerging chemical heterogeneities in a commercial 18650 Li-ion battery during early cycling
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DOI：
10.26434/chemrxiv-2022-4b442
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
D. Matras;T. Ashton;H. Dong;M. Mirolo;I. Martens;J. Drnec;J. Darr;P. Quinn;S. Jacques;A. Beale;A. Vamvakeros
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作者：
D. Matras;T. Ashton;H. Dong;M. Mirolo;I. Martens;J. Drnec;J. Darr;P. Quinn;S. Jacques;A. Beale;A. Vamvakeros
采用x射线衍射计算机断层扫描（XRD-CT）研究了商用18650圆柱形LiNi0.8Co0.15Al0.05O2 （NCA）电池在工作条件和7个循环下的性能。通过对空间分辨衍射信号的分析，发现阴极和阳极均存在与锂分布有关的多种化学非均质性。结果表明，在电池充电过程中，阳极在锂化过程中表现出不同程度的活性。明确确定了均匀/均质岩化区、延迟岩化区和非活跃岩化区。首次观察到的延迟锂化区域对电池放电过程中NCA的性能有直接影响，通过将锂以LiC30-30+相的形式捕获来阻止其完全锂化。除此之外，铝标签对与其直接接触的NCA产生了负面影响，导致与阴极其他部分相比，晶格参数a和c的演变不同。
X-ray diffraction computed tomography (XRD-CT) was employed to study a commercial 18650 cylindrical LiNi0.8Co0.15Al0.05O2 (NCA) battery under operating conditions and during seven cycles. Multiple chemical heterogeneities related to the lithium distribution were observed in both the cathode and the anode from the analysis of the spatially-resolved diffraction signals. It is shown that during the battery charging, the anode exhibits different degrees of activity regarding the lithiation process. Explicitly, the following three regions were identified: uniform/homogenous lithiation, delayed lithiation and inactive-to-lithiation regions. The delayed lithiation region, observed for the first time, was seen to have a direct impact on the properties of NCA in its close proximity during the battery discharging, preventing its full lithiation by trapping the lithium in the form of LiC30-30+ phase. Further to this, the aluminum tab negatively affected the NCA in direct contact with it, leading to different lattice parameter a and c evolution compared to the rest of the cathode.