Heterogeneous Damage in Li-Ion Batteries: Experimental Analysis and Theoretical Modeling
Heterogeneous Damage in Li-Ion Batteries: Experimental Analysis and Theoretical Modeling
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DOI：
10.1016/j.jmps.2019.05.003
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
Rong Xu;Yang Yang-Yang;Fei Yin;Pengfei Liu;P. Cloetens;Yijin Liu;Feng Lin;K. Zhao
中科院分区：
文献类型：
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作者：
Rong Xu;Yang Yang-Yang;Fei Yin;Pengfei Liu;P. Cloetens;Yijin Liu;Feng Lin;K. Zhao
我们使用同步加速器X射线断层扫描分析和微观结构分辨计算建模来评估商业电池复合电极中的非均相电化学和力学。我们可视化的形态缺陷在多尺度范围从宏观复合材料，颗粒合奏，到个别的单个颗粒。颗粒断裂和界面脱粘被确定在一个大的活性颗粒的层析数据集。在靠近分离器的区域中的机械故障比朝向集电器更严重。靠近分离器的活性颗粒在循环中经历更深的充电和放电，因此机械负载更大。Li活性的差异源于电解质电位的极化和电荷转移反应活化能的不均匀分布。我们模拟了晶间断裂和界面降解的动力学，以确认各种Li活动是异质损伤的主要原因。界面失效可以重建导电网络并重新分布电化学活性，这使得复合电极中的电化学和力学随时间推移而演变的动态性质。我们进一步量化了机械损伤对电池性能指标的影响。我们模拟的电化学阻抗分布建立界面脱粘之间的关系和电子传输和表面电荷转移的阻抗。机械故障破坏了电子的传导路径，并导致电池中的显著极化和容量损失。
We assess the heterogeneous electrochemistry and mechanics in a composite electrode of commercial batteries using synchrotron X-ray tomography analysis and microstructure-resolved computational modeling. We visualize the morphological defects at multi-scales ranging from the macroscopic composite, particle ensembles, to individual single particles. Particle fracture and interfacial debonding are identified in a large set of tomographic data of active particles. Mechanical failure in the regime near the separator is more severe than toward the current collector. The active particles close to the separator experience deeper charge and discharge over cycles and thus are more mechanically loaded. The difference in the Li activity originates from the polarization of the electrolyte potential and the non-uniform distribution of the activation energy for the charge transfer reaction. We model the kinetics of intergranular fracture and interfacial degradation to confirm that the various Li activities are the major cause of the heterogeneous damage. The interfacial failure may reconstruct the conductive network and redistribute the electrochemical activities that render a dynamic nature of electrochemistry and mechanics evolving over time in the composite electrode. We further quantify the influence of the mechanical damage on the metrics of battery performance. We simulate the electrochemical impedance profile to build a relationship between the interfacial debonding and the impedance of electron transport and surface charge transfer. The mechanical failure disrupts the conduction path of electrons and results in significant polarization and capacity loss in batteries.