This project we aim to formulate and numerically implement a constitutive framework for modeling the complex chemo-mechanical multi-particle interactions occurring in composite electrodes. Particularly, we seek to capture the variation in local current densities across surfaces of active particles through the use of chemo-mechanical surface (cohesive) elements. These elements capture the local, stress-coupled electrochemical potential and couple it to local mechanical interfacial damage.
In Bistri and Di Leo (JECS, 2021), we develop the first version of this work and demonstrate it first for modeling traditional liquid Li-Ion battery architecture with a focus on chemical interactions. Second, we model all-solid-state composite cathodes in 2D where mechanical multi-particle interactions are critical due to the presence of the stiff electrolyte matrix.
The image below shows an overview of the numerical framework where an RVE under galvanostatic charging conditions is considered. The RVE is discretized and the interfaces between the matrix and active particles are discretized with chemo-mechanical surface elements capturing the local non-linear reaction kinetics.
The image below shows a demonstration of this framework for a simple two-particle system. Here (a) shows the total current where we note we recover galvanostatic charging conditions even though the total current to each particle depend on material properties, stress, and damage. In (b) and (c) we highlight the manner in which current density over the two particles varies as damage evolves.
Bistri, D., Di Leo, C.V. “Modeling of chemo-mechanical multi-particle interactions in composite electrodes for Liquid and Solid-State Li-Ion Batteries.” Journal of The Electrochemical Society, 168(3), 2021. [html]
Video 1: Simulating cycling of 50 axisymmetric particles composed of a-Si/SiO2 double-walled hollow nano-tubes.
Video 2: Simulating composite solid-state Cathode behavior with focus on the behavior of a single particle.
Video 3: Simulating composite solid-state Cathode behavior with focus on varying particle size distributions.