Effect of a Heterogeneous Distribution of the Conductive Additives and Binder Domain on the Impedances of Lithium-Ion Battery Electrodes

Kurzfassung

The conductive additive and binder domain (CBD) is an essential component of Lithium-ion battery electrodes. It enhances the electrical connectivity and mechanical stability within an electrode matrix. Migration of the binder during electrode drying leads to an inhomogeneous distribution of the CBD, impeding transport of Lithium ions into the electrodes, and diminishing the electronic pathways between solid particles. Therefore, we investigate the effect of binder migration on the electrochemical performance of NMC622 electrodes via microstructure-resolved 3D simulations, and compare them with experimental results. The virtual electrode microstructures are based on tomographic data. The valuable information derived from combining microstructure-resolved models with electrochemical impedance spectroscopy (EIS) simulations on symmetric cells is used to characterize the Lithium-ion transport in the electrode pore space, including the contributions of the CBD. Additionally, half-cell discharge simulations are also conducted. Through our work, we demonstrate the significance of the CBD distribution and enable predictive simulations for future battery design.