Modeling the Impacts of Structural Heterogeneities on the Reaction-Transport Coupling in Porous Electrodes of Lithium-Ion Batteries Using Lattice Boltzmann Method

Abstract

Structural optimization of porous electrodes has been a practical route to improve the performance of lithium-ion batteries (LIBs). Currently, this relies mainly on the structure-featureless pseudo-two-dimension (P2D) model in the theoretical aspect, which is inherently contradictory to the emphasis on the importance of electrode structure. Herein, a 2D pore-scale LIBs model based on the lattice Boltzmann method (LBM) and the galvanostatic simulation scheme are established. The model is used to investigate the effects of physical structures on the coupling between ions transport and electrochemical reactions in porous electrodes, and the results are compared with a P2D model on the same electrode. The results show that for battery systems composed of homogeneously distributed structures, the LBM model gives nearly identical results to that of the P2D model. However, for battery systems with heterogeneously structured electrodes, obvious difference from the prediction of P2D model are obtained, especially at high C-rates. The P2D model significantly underestimates the structure-sensitive transport-reaction coupling and the non-uniform utilization of active materials, even when using the physical tortuosity based on electrode structure. These results emphasize the significance of developing a pore-scale model of LIBs based on realistic physical structure for the design of LIBs with satisfactory performance.