(Invited) Impact of Mesoscale Morphology on Electrode Performance through Multi-Physics Simulations

Abstract

While lithium-ion battery electrodes are manufactured in large-scale, high-speed, roll-to-roll manufacturing processes, it is the morphology of the particle and conductive binder structures that greatly affect macroscale properties and can vary significantly as a function of manufacturing conditions. This relationship is particularly true in the extremely fast (dis)charge environments relevant for electrification of our vehicle fleet, where the short time scales probe ever smaller length scales and increase the impact of ionic and charge transport limitations. To explore the process-structure-property relationship, we employ mesoscale finite element simulations of the three-phase particle-conductive binder-electrolyte composite of NMC cathodes. Particle and conductive binder domain mesostructures are derived from both x-ray computed tomography imaging and simulated using discrete element methods. The Conformal Decomposition Finite Element Method is applied to create conformal three-phase finite element discretizations of these mesostructures. Effective properties including electrical conductivity, tortuosity, and mechanical modulus are calculated and compared to experimentally measured values. Coupled electrochemical-mechanical simulations of cathode discharge are performed and validated against half-cell experimental data. We focus on how the conductive binder domain morphology affects electrode performance. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.