Synergistic Regulation of Interfacial Active Water and Zn Ion Flux for Achieving a Highly Reversible Zn Anode

The deleterious side reactions, uncontrollable dendrite growth, and surface passivation on the Zn anode prevent the further practical application of aqueous Zn-ion batteries (AZIBs). Herein, an alumina-based interface protective layer designed on the Zn anode realizes long cycle life and dendrite-free AZIBs. It theoretically and experimentally demonstrates that terminal oxygen and aluminum atoms can reduce the desolvation energy of Zn(H2O)62+ and improve the transport kinetics of Zn2+ at the interface. The stacked alumina particles in the protective layer can “attract-lock” the active water molecules and efficiently inhibit the side reactions on the Zn anode. Besides, the designed protective layer induces uniform electrolyte flux and facilitates bottom-up, uniform deposition of Zn2+. Based on the multiple optimization effects, an exceptionally high stability exceeding 4000 h with a cumulative plated capacity of 10 Ah cm–2 is achieved in a symmetrical cell. When the modified Zn anode is assembled with the manganese oxides, the electrochemical durability of the full battery can be improved from 52.8 to 70.3% after 5000 cycles. This work significantly enhances the cycling stability of the Zn anode and provides a meaningful reference for understanding the optimization mechanism of the artificial interface protective layer for high-performance AZIBs.