Zinc-Ion Conductive Metal-Organic Framework Interfaces for Comprehensive Anode Protection in High-Performance Aqueous Zinc-Ion Batteries.

Abstract

Aqueous zinc-ion batteries have attracted intensive attention because of their safety, low cost, and high theoretical capacity; however, their practical application is hindered by challenges, such as Zn dendrite formation, the hydrogen evolution reaction, and a limited cycle life. Herein, a zinc anode interface is prepared by combining sodium alginate (SA) with hydroxyl and carboxyl groups as a binder and zeolite imidazole framework (ZIF-7) as the ion transport channel. The carboxyl groups in SA exhibit strong Zn²⁺-ion affinity, forming a cross-linked structure with ZIF-7 and creating a self-reinforcing coating that promotes uniform Zn²⁺ ion flux while the ZIF-7 provides suitable ionic channels to enable oriented deposition. A ZIF-7/SA coated Zn anode (ZIF-7/SA@Zn) exhibited a high Coulombic efficiency of 99.7% after 1500 cycles at 10 mA cm^-2 and 1 mA h cm^-2. Even under high-current and high-capacity conditions (20 mA cm^-2, 20 mA h cm^-2), ZIF-7/SA@Zn maintained stable cycling for 500 h. When ZIF-7/SA@Zn was paired with a Zn_0.25V₂O₅ cathode, the resultant full cell retained more than 77.2% of its capacity after 10,000 cycles at 3000 mA g^-1. This work proposes a strategy to stabilize Zn anodes under high currents, advancing high-performance Zn-based energy storage systems.