Chemo-Mechanical Modeling of Stress Evolution in All-Solid-State Lithium- Ion Batteries Using Synchrotron Transmission X-ray Microscopy Tomography

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.