Impact of solid precipitate on the morphology and performance of Lithium-Sulfur battery cathodes using the lattice Boltzmann method

Abstract

Lithium-sulfur batteries (LIB) are a promising technology for next-generation energy storage. How-ever, LIB are affected by solid precipitate formation during cycling, which changes cathode morphol-ogy and passivates active surfaces, resulting in overall battery performance degradation. Morphological changes in the microstructure, from surface reactions, dissolution, and precipita-tion are difficult to characterise due to their complex interactions. Traditional computational method approaches typically use simplified abstract modelling [1,2] or homogenization relying on representa-tive volume elements [3]. However, accuracy and predictions of these approaches are limited. Never-theless, understanding these elusive phenomena are important to mitigate them in future LIB devel-opments. The driving dynamics and phenomena in LIB are mesoscopic in nature, where computational simulations can provide detailed insight.

In this work, a lattice Boltzmann method (LBM) model is presented that was specifically devel-oped to simulate the relevant physicochemical phenomena. The LBM has shown to outperform many conventional methods at the pore scale due to its sound physical basis and efficient computational parallelization.

Our model was applied to simulate and study three-dimensional porous cathodes, fully resolved in sub-micron resolution. The resulting simulations capture precipitates growth successfully and were used to investigate pore clogging and surface passivation. This study sheds light on the pore-scale happenings of LIB microstructures and will help to optimize the design of LIB systems.

Acknowledgements: Funded by the Federal Ministry of Education and Research with grant 03XP0491A