Uniform In Situ Grown ZIF-L Layer for Suppressing Hydrogen Evolution and Homogenizing Zn Deposition in Aqueous Zn-Ion Batteries.

Abstract

The hydrogen evolution and dendrite of Zn anode are the major troubles hindering the commercialization of aqueous Zn-ion batteries (AZIBs). ZIF-Ls, a typical metal-organic framework (MOF) with a highly ordered structure and abundant functional groups, seem to be the answer for the above bottlenecks. In this paper, a uniform ZIF-L layer was obtained on the Zn surface (Zn@ZIF-L) via an in situ synthesis method to moderate the solvation structure of solid-liquid interface electrolyte reducing the contact between water and Zn, thereby relieving the hydrogen evolution and corrosion. Furthermore, density functional theory (DFT) analysis reveals the binding energy of H (-4.01 eV) and Zn (-0.82 eV) for ZIF-L is superior to that of pure Zn (H (-1.49 eV) and Zn (-0.68 eV)). Due to the multifunctional ZIF-L layer, the Zn@ZIF-L can regulate Zn deposition to overcome the dendrite for obtaining a long-life Zn anode. Consequently, the modified Zn@ZIF-L anode can cycle for 800 h at 0.25 mA cm-2 for 0.25 mAh cm-2, while the bare Zn anode is only maintained for 422 h. Finally, a designed V2O5 grown on carbon cloth (V2O5@CC) was used as the cathode and coupled with the Zn@ZIF-L anode to assemble the full-cell. The Zn@ZIF-L//V2O5@CC full-cell possesses a capacity retention rate of 84.9% after 250 cycles at 0.5 C, prominently higher than Zn//V2O5@CC (40.7%).