Confinement of Zinc Salt in Ultrathin Heterogeneous Film to Stabilize Zinc Metal Anode

Abstract Aqueous zinc metal batteries (AZMBs) have drawn great attention due to the high theoretical capacity, low redox potential, and abundance reserves. However, the practical application of rechargeable AZMBs are hindered by the poor reversibility of Zn metal anode, owing to easy dendrite growth and serious side reactions. Herein, the preparation of heterogeneous interfacial film with highly dispersed and confined zinc salt in a 2D channel by coassembling polyamide 6, zinc trifluoromethanesulfonate, and layered double hydroxides, which significantly suppresses the dendrite formation, H 2 evolution reaction as well as O 2 corrosion is reported. The as‐developed Zn anodes exhibit a long cycling life up to 1450 h with low reversible deposition potential. Moreover, the assembled Zn||Mn battery delivers a high initial capacity of 321 mAh g −1 and a low capacity decay of ≈0.05% per cycle after 590 cycles, which is promising for high‐performance AZMBs. A fluorescent film to realize the in situ observation of the Zn anode during cycling, which provides a new chance for visual observation of the working state of the Zn interface, is also assembled.