Mechanical characterization and modeling of microstructural deformation of Si anode sheet

Battery anodes generally have a layered structure consisting of an active material layer (including binder, conductive carbon, and active material) and a foil layer of the current collector (copper foil). Such layered structures bring grand challenges to our understanding of the mechanical behaviors of the Si-based anode sheets since the large deformation of the Si particles, and solid-solid interfacial interactions (particle-particle and particle-binder) are key knowledge in high-energy, safe, and durable batteries. Herein, we characterize a typical commercialized Si-based anode with detailed microstructure morphology. Representative mechanical tests, including tensile and compression tests, are conducted to characterize the constitutive behaviors of the anode materials. Further, we propose a 3D computational model with detailed descriptions of the microstructures of the active material is established to enable a fundamental understanding of the deformation behaviors. Results present a comprehensive understanding of the Si-based anode materials for the first time and provide a powerful model for the future design of the anode for the next-generation batteries.