A framework for nucleation in electrochemical systems and the effect of surface energy on dendrite growth

Dendrite growth is directly attributed to the degradation of battery performance, and while many attributes of dendrite growth have been extensively studied, both experimentally and computationally, little is understood about the nucleation process and how surface chemistries and characteristics impact growth. In this study, a numerical model is presented to track the nucleation and growth of lithium dendrites when exposed to varying surface chemistries, in particular changes in surface energies. A combination of density functional theory (DFT) and continuum-level computational fluid dynamics is used to study the effects of surface energy on dendrite nucleation and growth. For a series of defects and concentrations, the DFT-calculated surface energies provide input to model dendrite nucleation and morphology in a lithium metal battery. The results suggest that different impurities can cause either an increase or decrease in surface energy with respect to a pristine lithium anode. For example, carbon impurities increase the surface energy and improve the stability of the interface leading to lithium plating that is dense and less dendritic. When the defects cause a decrease in surface energy there is significantly more dendrite growth. Finally, the interplay that surface energy and transport properties, due to the composition of the solid-electrolyte interphase (SEI) layer, have on dendrite growth is investigated showing that the dominating factor in the suppression of dendrite growth is improved Li+ transport through the SEI layer. The results presented throughout this work can inform approaches to engineering more stable anode-electrolyte interfaces and improved battery performance.