Kinetic understanding of lithium metal electrodeposition for lithium anodes.

ABSTRACT

Lithium, a representative alkali metal, holds the coveted status of the "holy grail" in the realm of next-generation rechargeable batteries, owing to its remarkable theoretical specific capacity and low electrode potential. However, the inherent reactivity of Li metal inevitably results in the formation of the solid-electrolyte interphase (SEI) on its surface, adding complexity to the Li electrodeposition process compared to conventional metal electrodeposition. Attaining uniform Li deposition is crucial for ensuring stable, long-cycle performance and high Coulombic efficiency in Li metal batteries, which requires a comprehensive understanding of the underlying factors governing the electrodeposition process. This review delves into the intricate kinetics of Li electrodeposition, elucidating the multifaceted factors that influence charge and mass transfer kinetics. The intrinsic relationship between charge transfer kinetics and Li deposition is scrutinized, exploring how parameters such as current density and electrode potential impact Li nucleation and growth, as well as dendrite formation. Additionally, the applicability of classical mass-transfer-controlled electrodeposition models to Li anode systems is evaluated, considering the influence of ionic concentration and solvation structure on Li+ transport, SEI formation, and subsequent deposition kinetics. The pivotal role of SEI compositional structure and physicochemical properties in governing charge and mass transfer processes is underscored, with an emphasis on strategies for regulating Li deposition kinetics from both electrolyte and SEI perspectives. Finally, future directions in Li electrodeposition research are outlined, emphasizing the importance of ongoing exploration from a kinetic standpoint to fully unlock the potential of Li metal batteries.