High-stable aqueous zinc metal anodes enabled by an oriented ZnQ zeolite protective layer with facile ion migration kinetics

Abstract

Aqueous zinc ion batteries (ZIBs) are regarded as one of the most promising energy storage systems due to their reliable safety, low cost, high volumetric capacity, and environmental friendliness. However, the utilization of Zn metal anode in aqueous electrolyte commonly encounters complex water-induced side reactions and uncontrollable dendrite growth issues. Constructing a protective layer on the surface of Zn anode is an effective strategy to alleviate side reactions and dendrite growth, achieving the stable operation of ZIBs with prolonged cycling life. However, the utilization of protective layers will increase interfacial resistance and result in high polarization in most cases. Thus, developing a desirable artificial protective layer with high ion migration kinetics is a significant task, enabling a fast Zn²⁺ ion flux for homogeneous deposition with low polarization. Considering that porous aluminosilicate zeolite with a low Si/Al ratio can accommodate abundant framework-associated cations as charge carriers for conduction, herein, we prepared an oriented protective layer on the Zn anode using Zn-ion-exchanged Q zeolite with BPH topology (ZnQ@Zn), achieving a stable Zn anode with high ion migration kinetics. The ZnQ zeolite plates parallelly lay on the surface of Zn foil with the c axis normal to the substrate plane. The three-dimensional ordered channels and the oriented arrangement of ZnQ zeolite plates provide facile ion migration pathways for Zn²⁺ ions, and the coordination of framework-associated Zn²⁺ ions with water in zeolite channels also enables fast ion conduction kinetics and high corrosion resistance. Therefore, ZnQ@Zn exhibits enhanced ion conduction kinetics with reduced energy barriers for desolvation, charge transfer, and diffusion processes, resulting in a uniform ion flux to suppress dendrite growth. Consequently, the ZnQ@Zn symmetric cell displays an ultra-low voltage hysteresis of 27 ​mV with a long lifespan of over 1100 ​h at 1 ​mA ​cm⁻² and 1 ​mAh ​cm⁻². Moreover, the ZnQ@Zn//NaV₃O₈·1.5H₂O full cell delivers a superior long-term cycling performance with a high capacity retention of 96% after 1800 cycles at 8 ​A ​g⁻¹. This work provides a new sight for constructing protective layers with fast ion migration kinetics to achieve high-stable Zn anodes, and extends the application of zeolite-based ion-conductive materials in energy storage devices.