Regulating Lithium Nucleation at the Electrolyte/Electrode Interface in Lithium Metal Batteries

Lithium (Li) metal has emerged as a viable alternative anode material to address the current energy density shortfalls in Li batteries. However, its integration into widespread implementation remains somewhat constrained due to the substandard reversibility issues and safety concerns arising from erratic Li deposition. To effectively tackle these obstacles, considerable endeavors have been exerted to modulate the morphology of Li deposition. Nevertheless, it is exceedingly challenging for Li nuclei that tend to dendritic growth thermodynamically to transform into dense Li morphologies during their growth process. Therefore, it is crucial to understand what influences the formation process of Li nuclei and how to improve the state of Li nuclei. Herein, Li nucleation mechanisms involving mass transport across the solid electrolyte interface from electrolyte to electrode and electrode interfacial reactions are elucidated. Inspired by the understanding of Li nucleation, the corresponding design principles, including enhancing and homogenizing mass transport, stabilizing solid electrolyte interface film, and regulating surface interaction/selection, are summarized for optimizing Li nucleation and further inducing dendrite-free Li deposition. In light of the competition among these design principles, a perspective on the existing challenges and opportunities for further promoting the application of Li metal batteries is proposed. The lithium dendrite growth is thermodynamically favorable after nucleation, so the early state of lithium nuclei is pivotal for uniform lithium deposition. The review summarizes the significant impact of both electrolyte-to-electrode mass transport and electrode interfacial reactions on lithium nucleation behavior, inspired design principles, and strategies for regulating lithium nucleation, and finally discusses the competitive relationships between these strategies.image