Bifunctional interface of metal–organic framework synergized with bismuth endows high stable zinc anode

Abstract

Zn-based aqueous batteries (ZnABs) are attractive in large-scale energy storage. However, the issues of hydrogen evolution and dendrite formation in zinc anode are the key challenges for this technology. Here, we demonstrate the metal bismuth encapsulated within a metal–organic framework (Bi@ZIF-8) as an artificial interface to protect the Zn anode. Revealed by electrochemical measurements and the in-situ optical images, the Bi@ZIF-8 interface makes for uniform deposition and simultaneously contributes to anti-corrosion in Zn anode. Hence, the symmetric Bi@ZIF-8 coated Zn foil (Bi@ZIF-8|Zn) cell exhibits the lowest polarization compared to ZIF-8|Zn and bare Zn, and achieves 420 h of operation at 7.5 mA cm−2. As a proof of concept, the elaborate alkaline Zn-Ni full cell based on Bi@ZIF-8|Zn anode shows excellent kinetic performance, a high coulombic efficiency of 98 %, and a long lifespan of 2500 cycles. Moreover, this Bi@ZIF-8 was used as a practical Zn electrode interface modifier, which endows a 2 Ah pouch cell with a high energy density of 130 Wh kg−1 and 420 Wh L–1. This research provides a novel thought for realizing long-life ZnABs via the artificial interface protection of the Zn anode.