Manipulating Lewis acid–base interactions in metal-organic frameworks for optimizing zinc-ion diffusion, deposition, and reaction behaviors

Abstract

The dendrite growth and side reactions of Zn anodes severely impair the performance of aqueous rechargeable Zn metal batteries. Although various artificial protective layers (APLs) have been developed to address these issues, the engineering of multifunctional APLs at the molecular level remains a challenge. Herein, a strategy of manipulating the Lewis acid–base interactions at the molecular level within metal-organic frameworks (MOFs) was conducted to optimize the Zn2+ diffusion, deposition, and reaction behaviors for stabilizing Zn anodes. A series of APLs based on isostructural UiO-66 type MOFs with different functional groups (–NH2, –OH, –SO3H, and –COOH) were developed to systematically study the influence of different host-guest interactions for zinc deposition. The results show that the more Lewis base chemical groups result in the improved ability of MOFs in trapping Zn2+, transporting Zn2+, accelerating the desolvation of Zn2+, regulating pH values, and decreasing the side reactions, rendering suppressed dendrite growth. Thus, UiO-66-2COOH shows the best performance in regulating Zn2+ deposition, delivering an excellent Zn plating/stripping cycling of up to 2700 h at 1 mAh/cm2 and 1600 h at 5 mAh/cm2, as well as full cells with remarkably improved C-rate and cycling performance.