Progressive interface debonding in composite electrodes of Li-ion batteries via mixed-mode cohesive zone model: Effects of binder characteristics

摘要

A considerable portion of the electrode is made of non-active materials such as binders, these not only regulate the ionic and electronic diffusion pathways, but also play an important role in enhancing the mechanical stability of the active materials. The volumetric expansion/contraction associated with lithiation/delithiation of the active material may lead to particle-binder interfacial debonding, which in turn disrupts the lithium and electronic conduction in the electrode. Since the morphological and material properties of the binder greatly vary in the particle-binder network, in this paper, the effects of binder features on interfacial debonding are investigated using two-way coupling of the chemo-mechanical and mixed-mode cohesive-zone models. The series of simulations we carried out showed that increases in active particle size and binder content prevent debonding, in contrast, increases in the Young's modulus and ionic conductivity of the binder promote debonding.