Chemomechanical interplay of layered cathode materials undergoing fast charging in lithium batteries
Chemomechanical interplay of layered cathode materials undergoing fast charging in lithium batteries
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DOI：
10.1016/j.nanoen.2018.09.051
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发表时间：
2018-11
期刊：
影响因子：
17.6
通讯作者：
Sihao Xia;Linqin Mu;Zhengrui Xu;Junyang Wang;Chenxi Wei;Lei Liu;P. Pianetta;K. Zhao;Xiqian Yu-Xiqia
中科院分区：
文献类型：
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作者：
Sihao Xia;Linqin Mu;Zhengrui Xu;Junyang Wang;Chenxi Wei;Lei Liu;P. Pianetta;K. Zhao;Xiqian Yu-Xiqia
形态缺陷会导致电池的慢性和急性故障。这些形态缺陷的发展需要与内部机械应力相关的多尺度化学机械耦合。由各向异性结构、化学和荷电状态 (SOC) 异质性引起的机械应力通过裂纹形成释放，破坏电子和离子的连续扩散路径，并为电极-电解质副反应创造新的表面。对化学机械相互作用的理解仍停留在描述性水平，因此，非常需要对这些过程进行指纹识别的量化或模型。在此，我们系统地研究了经过快速充电条件的LiNi0.6Mn0.2Co0.2O2二次颗粒内的介观形态缺陷。借助先进的同步加速器 X 射线断层扫描，我们无损地刺穿次级粒子的内部体积，并量化裂纹形成的形态结果，例如孔隙率和内表面积。然后，我们开发了一个数值模型来预测裂纹引起的电子和锂离子扩散威慑。局部离子电导率和电子电导率之间的不匹配会导致二次粒子中高度不均匀的 SOC 分布，随着电流密度的增加，SOC 分布呈指数级恶化。我们对化学机械相互作用和快速充电的深入研究可以为知识库提供信息，以加速发现能够抵抗化学机械故障的先进材料。
Morphological defects contribute to chronic and acute failures of batteries. The development of these morphological defects entails the multiscale chemo-mechanical coupling associated with internal mechanical stress. The mechanical stress, caused by anisotropic structural, chemical and state of charge (SOC) heterogeneities, is released through crack formation, undermining the continuous diffusion pathways of electrons and ions and creating fresh surfaces for electrode–electrolyte side reactions. The understanding of chemomechanical interplay has remained at the descriptive level, thus, the quantification or model to fingerprint these processes is highly desired. Herein, we systematically investigate the mesoscale morphological defects within LiNi0.6Mn0.2Co0.2O2secondary particles that have gone through fast-charging conditions. With the advanced synchrotron X-ray tomography, we nondestructively pierce the internal volume of secondary particles and quantify the morphological outcomes of the crack formation, such as porosity and internal surface area. We then develop a numerical model to predict the crack-induced diffusion deterrent of electrons and lithium ions. The mismatch between the local ionic and electronic conductivity can lead to highly heterogeneous SOC distribution in secondary particles, which exponentially deteriorates as the current density increases. Our incisive investigation of chemomechanical interplay and fast-charging can inform a knowledge base to accelerate the discovery of advanced materials that are resilient against chemomechanical failures.