Abstract

In this study, a chemo-mechanical modeling framework was developed by adopting a reconstructed three-dimensional morphology of all-solid-state lithium-ion battery (ASSB) composite electrodes, using a synchrotron transmission X-ray microscopy tomography system. The developed model aimed to elucidate the effects of the electrode microstructure, specifically solid electrolyte/active material (SE/AM) interface and void space, toward the lithiation-induced stress evolution. The results show that the peak stress points happen at the SE/AM interface, while void space can partially accommodate the AM swelling and alleviate the stress formation. Although applying higher pressing pressure during the electrode fabrication can improve the ion pathways, it adversely affects the stress formation and may cause crack propagation. The results reveal that SE stiffness has a key impact on stress formation and AM displacement. Although employing SE with a lower stiffness can attenuate the stress within the microstructure, it can exacerbate the anisotropic displacement of AM particles. In contrast, applying external pressing pressure can prevent anisotropic displacement of AM particles. The developed framework highlights the significance of microstructural design of ASSBs and provides invaluable insights.

摘要

在这项研究中，通过采用全固态锂离子电池（ASSB）复合电极的重构三维形态，并采用同步加速器透射X射线显微镜层析成像系统，开发了化学机械建模框架。开发的模型旨在阐明电极微结构（特别是固体电解质/活性材料（SE / AM）界面和空隙）对锂化诱导应力演化的影响。结果表明，峰值应力点出现在SE / AM界面，而空隙空间可以部分容纳AM膨胀并减轻应力形成。尽管在电极制造过程中施加较高的压力可以改善离子通道，但会对应力形成产生不利影响，并可能导致裂纹扩展。结果表明，SE刚度对应力形成和AM位移具有关键影响。尽管采用具有较低刚度的SE可以减弱微结构内的应力，但可以加剧AM粒子的各向异性位移。相反，施加外部压力可以防止AM颗粒的各向异性位移。开发的框架突出了ASSB的微结构设计的重要性，并提供了宝贵的见解。