Impact of Lithium‐Ion Coordination on Lithium Electrodeposition

Abstract

The lithium dendrite and parasitic reactions are two major challenges for lithium (Li) metal anode—the most promising anode materials for high‐energy‐density batteries. In this work, both the dendrite and parasitic reactions that occurred between the liquid electrolyte and Li‐metal anode could be largely inhibited by regulating the Li+‐solvation structure. The saturated Li+‐solvation species exist in commonly used LiPF6 liquid electrolyte that needs extra energy to desolvation during Li‐electrodeposition. Partial solvation induced high‐energy state Li‐ions would be more energy favorable during the electron‐reduction process, dominating the competition with solvent reduction reactions. The Li‐symmetric cells that are cycling at higher temperatures show better performance; the cycled lithium metal anode with metallic lustre and the dendrite‐free surface is observed. Theoretical calculation and experimental measurements reveal the existence of high‐energy state Li+‐solvates species, and their concentration increases with temperature. This study provides insight into the Li+‐solvation structure and its electrodeposition characteristics.