Dendrite-Free Zn Anode Endowed by Facile Al-Complex Coating for Long-Cycled Aqueous Zn-Ion Batteries

Side reactions and dendrite growth on the zinc metal anode surface seriously damage the shelf life and calendar life of Zn-based batteries. Here, an Al-complexed artificial interfacial layer is constructed on the Zn surface (denoted as Al-complex@Zn) by a low-cost, facile, and scalable chemical method. The Al-complex interfacial layer improves the wettability of the electrolyte. Meanwhile, the Al-complex layer not only inhibits the side reaction by a physical barrier on the Zn surface but also regulates the zinc-ion flux to realize the uniform deposition of Zn²⁺. The Zn//Zn symmetric cell with an Al-complex layer has realized an ultralong cycle life of 2400 h and an extremely low polarization voltage of 20 mV (1 mA cm^-2, 0.5 mAh cm^-2), surpassing those reported in most literature. Furthermore, when an Al-complex@Zn//NaV₃O₈·1.5H₂O (NVO) full cell is assembled, a high capacity retention of 92.5% is achieved over 1000 cycles at a current density of 4 A g^-1. This work provides a facile and low-cost strategy on the modification of zinc anode to realize long-cycled aqueous Zn-ion batteries.