In Situ Construction of Hydrophobic Interfacial Layer with Multitude Zincophilic Sites for Stable Zinc Metal Anode

Aqueous zinc-ion batteries show promising potential for energy storage applications. However, they face challenges such as dendrites growth and uncontrollable side reactions at the zinc anode, which require effective solutions. In this study, we successfully addressed these issues by implementing in situ zinc complex formation reactions to construct hydrophobic protective layers on the zinc anode surface. These robust interfacial layers serve as barriers, facilitating the efficient isolation of the Zn anode from the electrolyte and active water molecules resulting from the desolvation of Zn(H2O)62+. This isolation leads to the effective suppression of hydrogen evolution and the formation of byproducts. Additionally, the multitude of zincophilic sites originating from functional groups within these complex protective layers promote uniform zinc deposition while inhibiting dendrite growth. Following an evaluation of functional anodes with various types of functional groups and varying lengths of alkyl chains, we meticulously examined the intrinsic mechanisms contributing to differences in performance. This analysis encompassed the precise control of interfacial hydrophobicity, rapid Zn2+ ion transport, and ordered Zn2+ ion deposition. Notably, the optimized anode, fabricated with octadecylphosphate (OPA), demonstrated superior performance, in which the configured Zn//Zn symmetric cell exhibited a remarkable longevity of over 4000 hours at a current density of 2 mA cm-2 and a capacity density of 2 mAh cm-2. Furthermore, when coupled with a VOH cathode, the full cell displayed superior capacity retention compared to anodes modified with other organic molecules.