(Best Student Presentation) Impact of Surface Characteristics on Interfacial Stability in Lithium Metal Batteries

A comprehensive understanding of the morphology evolution of deposited lithium (Li) is a primary challenge in the commercialization of Li-metal batteries. Li-metal batteries, which contain a Li-metal anode, have a theoretical capacity that is an order of magnitude greater than that of a Li-ion battery helping to overcome their energy storage limitations. However, while Li-metal batteries have proven to have a much larger specific capacity, they are hindered by unstable deposition at the electrode-electrolyte interface and severe dendritic growth. Interfacial stability is a complex phenomenon that is influenced by many different factors, including local current densities, overpotentials, Li+ concentrations, and transport properties. Additionally, varying surface characteristics such as surface chemistries and the physical structure of the anode can affect Li deposition and could be used to design a more stable interface. Due to the nature of the anode surface, it is difficult to observe the complex physics experimentally. Thus, computational modeling is a powerful tool for understanding the deposition of Li on the anode surface. In this work we present a computational model to comprehensively study the morphology of dendrites when exposed to varying conditions. While transport properties1, electrolyte characteristics2, separator structures3, and charging protocols4 play significant roles in Li dendrite morphology and interfacial stability, this work focuses on the impact of the anode surface itself on stability. This includes patterned anode surfaces for guided lithium deposition and varying surface chemistries such as surface energy and reaction rate. We concentrate on the types of defects that are present along the anode surface including surface roughness, points of high convexity, breaks in the SEI layer, lattice defects leading to changes in surface energy and their impact on instability. We also look at guided deposition through modifications of the anode surface. 1. J. Tan, A. M. Tartakovsky, K. Ferris, and E. M. Ryan, J Electrochem Soc, 163, A318–A327 (2016). 2. J. Tan and E. M. Ryan, J Power Sources, 323, 67–77 (2016). 3. A. Cannon and E. M. Ryan, ACS Appl Energy Mater, 4, 7848–7861 (2021). 4. T. Melsheimer, M. Morey, A. Cannon, and E. Ryan, Electrochim Acta, 433 (2022).