Dual‐Site Catalytic Interfaces Synergistically Boost Desolvation and Redox Kinetics in Zinc‐Ion Batteries

Abstract

ABSTRACT Aqueous zinc‐bromine batteries hold significant promise for large‐scale energy storage owing to their intrinsic safety, high operating voltage and low cost. Their deployment, however, is limited by sluggish Zn 2 + desolvation at the anode/electrolyte interface and sluggish redox kinetics of bromine species at the cathode. In this work, we developed a dual‐site catalytic interface that selectively accelerates interfacial kinetics without altering the bulk electrolyte. On the anode‐facing side, the indium acetylacetonate molecules provide soft Lewis acid In 3 + sites that weakly coordinate with water and interact with solvated Zn 2 + , effectively lowering Zn 2 + desolvation energy and enabling uniform, dendrite‐free zinc deposition. On the cathode‐facing side, the copper acetylacetonate molecules offer redox‐active Cu 2 + /Cu + sites that catalyze the Br 0 /Br − conversion, accelerating reaction kinetics and improving reversibility. As a result, the desolvation energy barrier decreases by approximately 21% (from 39.69 to 31.25 kJ·mol −1 ). The zinc‐bromine battery with dual‐site interface delivers a high specific capacity exceeding 293.8 mAh·g −1 at 0.2 A·g −1 , which reaches approximately 87.5% of the theoretical capacity of pure bromine (335.5 mAh·g −1 ). Our findings reveal that targeted interfacial catalysis can overcome kinetic bottlenecks in zinc batteries while preserving the intrinsic properties of the electrolyte, offering a general strategy for high‐performance energy storage systems.