In-Situ Nanoindentation Measurement of Local Mechanical Behavior of a Li-Ion Battery Cathode in Liquid Electrolyte
In-Situ Nanoindentation Measurement of Local Mechanical Behavior of a Li-Ion Battery Cathode in Liquid Electrolyte
复制标题
DOI：
10.1007/s11340-018-00451-6
复制
发表时间：
2018-11
影响因子：
2.4
通讯作者：
L. S. de Vasconcelos;N. Sharma;R. Xu;K. Zhao
中科院分区：
文献类型：
--
作者：
L. S. de Vasconcelos;N. Sharma;R. Xu;K. Zhao
最先进的阴极材料在锂化循环中经历严重的结构和机械退化，尽管它们的变形很小。由于复合电极的环境敏感性和复杂的微观非均匀性，其力学行为的现场和实时表征一直是一个巨大的挑战。我们使用纳米压痕测量在阴极复合电极LiNixMnyCozO2中的各个相的原位机械行为。我们专注于在干燥和潮湿条件下的组分的机械性能的理解。我们评估电解质浸泡的弹性模量，硬度，和体积变化的导电基体具有不同程度的孔隙率的影响。更有趣的是，我们测量了聚集的活性颗粒和烧结颗粒的模量、硬度和断裂强度，并比较了它们在干燥和液体环境中的机械性能。我们发现，电解质提高了断裂强度的NMC团聚颗粒。界面强度的增加可能是初级颗粒之间的附加毛细力的结果。研究结果提供了对复合电极复杂行为的机理理解，并将为锂离子电池的化学力学模型提供支持。
The state-of-the-art cathode materials experience severe structural and mechanical degradation over lithiation cycles albeit their small deformation. It has been a great challenge to characterize the mechanical behavior of composite electrodes in-situ and in real-time because of their environmental sensitivity and intricate microscopic heterogeneity. We use nanoindentation to measure the in-situ mechanical behavior of individual phases in a cathode composite electrode LiNixMnyCozO2. We focus on the understanding of the mechanical properties of the constituents in dry and wet conditions. We evaluate the influence of electrolyte soaking on the elastic modulus, hardness, and volume change of the conductive matrix with different degrees of porosity. More interestingly, we measure the modulus, hardness, and fracture strength of agglomerated active particles and sintered pellets, and compare their mechanical properties in the dry and liquid environment. We show that the electrolyte enhances the fracture strength of NMC agglomerated particles. The increase in interfacial strength may be a result of the additional capillary force between primary particles. Results offer mechanistic understanding of the complex behavior of composite electrodes and will feed chemomechanical models on Li-ion batteries.