Dissolution and Precipitation in Conversion-Type Battery Systems using Lattice Boltzmann Method

Abstract

Metal-sulfur batteries, such as lithium-sulfur (Li-S) for aerial and magnesium-sulfur (Mg-S) for ground-based applications [1] are a promising alternative to today's Lithium-ion batteries. In its development process, beside experiments, conventional continuum simulation approaches are applied. While many one-dimensional models [2] have been used to describe and analyse the charge and discharge behaviour of such systems, only few incorporate the physical complexity of these conversion-type batteries. Either the realistic physical behaviour is strongly abstracted [3,4] or modelled using a single volume element as a representative electrode structure [5]. However, a detailed understanding and insight into how pore-scale behaviour affects the cell level is still missing. In this contribution, a novel LBM model is presented and used to simulate the relevant aspects of multi-species transport phenomena and chemical reactions at the pore-sacle, including dissolution and heterogeneous precipitation. This model is applied to three-dimensional porous electrodes which are studied fully resolved in sub-micron resolution. Electrochemical effects are incorporated via the reaction pathways. As such, crystal growth, pore clogging, and polysulfide diffusion, are studied in detail. The effects of surface passivation, temporal varying tortuosity, diffusion pathways, available reactive surface, and capacity loss will be analysed. [1] Richter, R. et al. (2021) ACS Appl. Energy Mater., 4(3), pp. 2365-2376. [2] Kumaresan, K. et al. (2008) J. Electrochem. Soc., 155(8), p. A576. [3] Danner, T. and Latz, A. (2019) Electrochim. Acta, 322, p. 134719. [4] Ren, Y.X. et al. (2016) J. of Power Sources, 336, pp. 115-125. [5] Mistry, A. and Mukherjee, P.P. (2017) J. Phys. Chem. C, 121(47), pp. 26256-26264.