Bridging Li-S nucleation phenomenon to macroscopic relations using resolved lattice Boltzmann method

Abstract

Lithium-sulfur (Li-S) batteries hold promise as a post lithium-ion technology due to their high gravimetric energy density, but their performance and design require further optimization. Assisting in that, continuum models on the cell scale are used to describe the charge and discharge behavior, among other characteristics. However, the solid charge and discharge formation processes are typically not resolved, but described via empirical correlations. To bridge the gap between microscopic nucleation phenomena and macroscopic cell behavior, we developed a resolved lattice Boltzmann method (LBM) model. This approach captures the complex interactions between physicochemical phenomena, such as polysulfide diffusion, electrochemical effects, dissolution, and precipitation, at the pore scale. Our LBM model simulates three-dimensional porous cathodes with sub-micron resolution, enabling the study of nucleation and precipitate growth, and its impact on pore clogging and surface passivation. By resolving the microstructure, we establish a direct link between nucleation phenomena and macroscopic cell performance. This novel approach provides valuable insights into the pore-scale behavior of Li-S batteries, ultimately contributing to the design and optimization of these systems.