Modeling Lithium Stripping and Plating

Lithium-metal anodes are an indispensable ingredient of next-generation lithium battery concepts, as they offer energy densities comparable to those of new cathode chemistries, e.g., Li-O₂ and Li-S. However, lithium-metal anodes undergo morphologic changes during battery cycling which reduces battery performance and safety. Lithium plating on standard graphite anodes is a related phenomenon. At low temperatures or high rates, lithium can deposit on the graphite surface as metal instead of intercalating.

Here, we approach crystallization of lithium metal from two directions. On a mesoscopic level, we model the dissolution of lithium metal. Experimentally, droplet formation, i.e., lithium stripping, was observed during the dissolution of lithium dendrites [1]. Based on our models for electrochemically-driven surface growth [2–4] inspired by phase-field modeling [5], we accurately describe lithium dendrite dissolution. In our model, the interaction between SEI and lithium metal is responsible for the nucleation of a Rayleigh-Jeans instability leading to droplet formation [6] driven by the lithium metal surface energy.

On a macroscopic level, we model lithium plating in a three-dimensional thermal transport and reaction model of the full battery cell. Our model accounts for consistent transport [7] and reaction [4] kinetics in electrolyte and electrode particles in order to understand the influence of inhomogeneous nucleation of lithium metal in a graphite anode on the battery performance.

Literature

[1]       J. Steiger, D. Kramer, and R. Mönig, To Be Submitt. (2013).

[2]       B. Horstmann, B. Gallant, R. Mitchell, W. G. Bessler, Y. Shao-Horn, and M. Z. Bazant, J. Phys. Chem. Lett. 4, 4217–4222 (2013).

[3]       M. Z. Bazant, Acc. Chem. Res. (2013).

[4]       A. Latz and J. Zausch, Electrochim. Acta 110, 358–362 (2013).

[5]       L. Liang, Y. Qi, F. Xue, S. Bhattacharya, S. J. Harris, and L.-Q. Chen, Phys. Rev. E 86, 051609 (2012).

[6]       J. Eggers, Rev. Mod. Phys. 69, 865–929 (1997).

[7]        A. Latz and J. Zausch, J. Power Sources 196, 3296 (2011).