Highly Reversible Zn Metal Anode Enabled by Interfacial Water Pocket

The zinc metallic anode encounters significant challenges stemming from vigorous and prolonged water-induced side reactions along with uncontrolled dendritic Zn growth, resulting in a notable decrease in the Coulombic efficiency (CE) and longevity of aqueous zinc batteries (AZBs). To mitigate the negative impacts of water's reactivity, a robust aluminum-centered metal–organic framework (MOF) is utilized. This MOF features a water pocket embedded within its subnano channels, serving to safeguard the Zn anode. The water pocket within narrow channels captures water molecules originating from solvated Zn2+, facilitating gradual desolvation, thus eliminating water-induced corrosion and side reactions. Essentially, the modified subnano channels act as ion rectifiers, aiding swift and even Zn2+ transfer, thereby averting dendrite creation on the Zn metal. Consequently, the shielded Zn metal exhibits unparalleled cycling stability, surpassing 2000 cycles, and an exceptionally high average CE of 99.47%. Moreover, the modified MOF@Zn|KVOH (KV12O30-y·nH2O) cell demonstrates a consistent cycling performance, achieving 6000 cycles at 5 A g–1. This groundbreaking approach for enhancing the reversibility of Zn metal anodes could drive the practical adoption of AZBs.