A systematic implementation of the solid electrolyte interphase layer and study of its impact on lithium plating morphology in lithium metal batteries

M Morey and M Lobel and E Ryan, JOURNAL OF ENERGY STORAGE, 122, 116731 (2025).

DOI: 10.1016/j.est.2025.116731

Dendrite growth and non-uniform deposition at the anode-electrolyte interface pose safety concerns and hinder the commercialization of high energy density, rechargeable lithium metal batteries. Li deposition is influenced by many factors including surface chemistries, such as reaction rate and interfacial energy, local Li+ concentration gradients, and surface heterogeneities. In particular, the Solid Electrolyte Interphase (SEI) layer is a key factor causing instability at the interface. However, the embedded nature of the anode-electrolyte interface makes it difficult to observe and study experimentally; alternatively, computational modeling can explicitly resolve the interface and be an effective tool to understand Li deposition behavior. The SEI layer is a chemically complex, dynamic layer that is not well understood. In this paper a novel computational model is used to evaluate three computational approaches to implement the SEI, which allows for a manageable, yet representative incorporation of this layer. These approaches are then combined to study how the physical parameters of the SEI layer impact plating stability showing that thin and highly conductive layers with large interfacial energies can aid in suppressing dendrite growth. Finally, the complexity that is required to accurately capture the SEI physics is evaluated and presented indicating that it is critical to consider the impact that the SEI layer has on the Li ion transport and interfacial energy. Additionally, for complex interfacial geometries, like mechanically patterned anodes, a non-uniform reaction rate and breaks in the SEI layer are important to consider.

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