Effect of current collector on the coupled electro-chemo-mechanical performance of graphite electrodes in LiBs

The current collector, one of the main components in the manufacture of composite electrodes, is mainly used to enhance the mechanical stability and improve the performance and cycle performance of the electrodes. During the electrochemical reaction, the lithium diffusion can induce compressive stress and affect the mechanical performance, lifespan, and performance of batteries. Therefore, this study analyzed the influence of copper foil on the mechanical response and degradation performance of electrodes. In addition, a mathematical model was developed to analyze the effect of copper foil on the stress-strain behavior of the electrodes. The results indicated that the stress and modulus of the graphite electrodes have a non-linear increase with the lithiation process. Based on those findings, utilizing a thinner and more compliant current collector could effectively mitigate the in-plane strain and the stress within electrodes. Thus, developing a thinner and softer copper foil could simultaneously enhance the mechanical properties and specific density of composite electrodes for the next-generation LiBs.