Zn(II)−Salen Complexes for Surface Engineering of Zn Anodes in Aqueous Zinc Ion Batteries

Aqueous zinc-ion batteries are attractive for large-scale energy storage but are limited by dendrite growth and side reactions at the Zn anode. In this work, we design a functional coating strategy using Zn-Schiff base complexes to overcome these issues. The complexes, featuring abundant coordination sites and ionic conductivity, modulate Zn²⁺ transport and promote desolvation, ensuring uniform deposition. Three complexes-Zn-salen, Zn-salpn, and Zn-salbn-were developed, among which Zn-salbn exhibited the best performance. Symmetric Zn||Zn cells with Zn-salbn@Zn anodes cycled stably for 2310 h at 1 mA cm^-2/1 mAh cm^-2 with a low overpotential of 31.9 mV, while delivering a high average Coulombic efficiency of 99.7%. In full cells, pairing Zn-salbn@Zn with V₂O₅ enabled 83.1% capacity retention after 1000 cycles at 0.5 A g^-1. This work not only demonstrates the effective protection of Zn metal anodes by Schiff base complexes, but also provides new insights into the application of interfacial chelation strategies in next generation high performance energy storage technologies.