Size-and-thickness-dependent fracture patterns of hollow core–shell electrodes during lithiation

Abstract

Conventional materials for lithium-based rechargeable batteries are reaching their limit. Material failure is also a huge barrier to fully exploit the potential. Novel design of nanomaterials provides possible solutions for these problems. However, the mechanism of material failure during lithiation/delithiation cycling is still not well understood. Here we develop a concurrently coupled chemo-mechanical model based on peridynamics to study the fracture-pattern formation of hollow core–shell structures during lithiation. We show that the geometric parameters of the nanostructures may profoundly influence the behaviors of dynamic fracture, i.e., different coating thicknesses and sizes of the nanotubes lead the cracks to branch in different directions, making them grow into different patterns. We investigate the stress state to explore the reason for the differentiation. A phase diagram for fracture patterns is constructed to have a systematic view. The results in this work provide a basis of designing the nanostructures of the electrode materials in the future.