A Diffusion-Reaction Mechanism Promoting Spherical Li Deposition

Abstract

Li metal is recognized one of the most promising anode materials owing to its ultrahigh theoretical specific capacity of 3860 mAh cm−2 and lowest electrochemical potential of −3.04 V vs. standard hydrogen electrode. Nonetheless, Li metal anode has been dramatically hindered from practical application by the dendritic Li growth. Regulating the Li deposition into spherical is an effective approach to avoid issues caused by Li dendrites, where the mechanism of forming spherical deposition is unknown. In this contribution, a diffusion-reaction competition mechanism is prospected to reveal the “truth” of spherical Li deposition. Based on the model experiment date through controlling the Li ion diffusion and reaction step, Li deposition morphology map is gained to verify that the diffusion and reaction step synergistic determine the ion concentration beneath the SEI and therefore regulate the Li deposition morphology. This study provides further fundamental understanding of Li plating and directly promotes safe Li metal battery design to benefit future wireless and fuel-free world. Figure 1