Chemo-mechanical response of composite electrode systems with multiple binder connections

Abstract

In Li-ion batteries, the feature of inter-particle connection of a non-active binder can affect lithium diffusion inside the particle and stress development due to the diffusion–stress coupling effect, leading to change in the failure mechanisms of the electrode. In this study, to investigate the effect of binder connection feature on mechanical response, a series of simulations is carried out by changing the particle radius for three cases of single, double, and triple binder connections. The effects of C-rates, lithium flux at the particle–binder interface, level of mechanical constraint, and binder content on the stress development in the particle, binder, and interface domains are explored. We find that two effects of binder confinement and concentration gradients compete in the stress development. For small particles, the binder confinement effect is dominant; while for large particles, the concentration gradients effect is dominant. In addition, the single binder model shows a different stress trend, compared to the multiple binder models, due to asymmetric constraint from the binder. The insights obtained from this study help in the design of composite electrode materials for enhanced battery performance by optimizing parameters.