Cerium‐Mediated Redox Chemistry in MOF Coatings Enables Ultrastable Aqueous Zn Metal Batteries

ABSTRACT

Constructing artificial coatings on Zn metal anodes represents a promising approach to suppressing interfacial side reactions and enhancing reversibility for stable aqueous Zn metal batteries. Herein, Ce‐mediated redox chemistry in Ce‐UiO‐66 MOF coating was explored to stabilize the aqueous Zn anode. We found that the Ce‐UiO‐66 coating facilitates multi‐stage Zn ²⁺ desolvation due to its abundant carboxyl groups and an optimal porous structure. Moreover, the Ce ³⁺ /Ce ⁴⁺ redox‐induced, abundant vacancies provide numerous zincophilic sites for preferential Zn ²⁺ adsorption and transport. Crucially, the reversible Ce ³⁺ /Ce ⁴⁺ redox behavior enables significant homogenization of electron/Zn ²⁺ distributions while accelerating interfacial charge transfer kinetics during repeated Zn plating/stripping. Consequently, a Zn anode with an optimal ∼5 µm Ce‐UiO‐66 coating achieves exceptional stability, highlighted by an ultralong cycling life exceeding 6000 h at 2.0 mA cm ⁻² and 1.0 mAh cm ⁻² , alongside an ultralow polarization voltage of ∼24 mV. High‐rate stability over 2800 h is also maintained at 5.0 mA cm ⁻² and 1.0 mAh cm ⁻² . This work underscores the great potential of redox‐active coatings, specifically leveraging Ce‐mediated redox chemistry, to enable highly stable aqueous Zn metal batteries for practical applications.