Detailed computational modeling of crack patterns of silicon-based anode sheet in lithium-ion batteries upon mechanical stress

Silicon (Si)-based anodes, where Si serves as the active material, have garnered significant attention due to their potential to achieve high electric capacity in lithium-ion batteries (LIBs). A key challenge with Si-based anodes is their susceptibility to create in-plane cracks caused by stresses from the manufacturing process and cyclic charging, which ultimately shortens battery life and reduces the overall electrochemical capacity. To address this issue, a refined microstructural design of the active material layer is in pressing need to enhance both the performance and longevity of LIBs. We successfully applied the Oyane failure criterion, which models ductile failure under stress triaxiality, to simulate crack initiation and propagation in the binder matrix containing Si particles in the finite element modeling. Given the non-linear plastic deformation of the binder, this criterion was formulated based on cumulative strain increments. The computational results of microcrack formation within the active material layer under uniaxial tension were then validated by the experimental observations. Furthermore, we developed several models with varied particle arrangements, comparing each simulated crack path to actual microstructural images obtained via scanning electron microscopy. The findings confirm the accuracy of the model, underlying its promising application in optimizing the microstructure of Si-based anodes for enhanced LIB performance and durability.