In Situ Construction of a Multifunctional Quasi-Gel Layer for Long-Life Aqueous Zinc Metal Anodes

Aqueous zinc (Zn)-ion batteries are considered very promising in grid-scale energy storage systems. However, the dendrite, corrosion, and H₂ evolution issues of Zn anode have restricted their further applications. Herein, to solve these issues, a hydrophilic layer, consisting of a covalent organic polymer (COP) and carboxylmethyl cellulose (CMC), is designed to in situ construct a multifunctional quasi-gel (COP-CMC/QG) interface between Zn metal and the electrolyte. The COP-CMC/QG interface can significantly improve the rechargeability of the Zn anode through enhancing Zn²⁺ transport kinetics, guiding uniform nucleation, and suppressing Zn corrosion and H₂ evolution. As a result, the COP-CMC-Zn anode exhibits a reduced overpotential (12 mV at 0.25 mA cm^–2), prolonged cycle life (over 4000 h at 0.25 mA cm^–2 and 2000 h at 5 mA cm^–2 in symmetrical cells), and elevated full-cell (Zn/MnO₂) performance. This work provides an efficient approach to achieve long-life Zn metal anodes and paves the way toward high-performance Zn-based and other metal-ion batteries.