Immiscibility‐Driven Exsolution Engineering of Practical Zn Powder Anodes for Ultrafast and Reversible Zn Ion Reduction

ABSTRACT

Zinc (Zn) powder is a promising anode material for aqueous zinc‐ion batteries (AZIBs) because of its low cost, structural tunability, and compatibility with established industrial manufacturing processes. Its practical implementation, however, is severely hindered by sluggish Zn ²⁺ /Zn redox kinetics and pronounced interfacial side reactions. Here, by exploiting the intrinsic thermodynamic immiscibility between Zn and Cd, we develop an exsolution strategy via powder metallurgy to uniformly anchor semi‐coherent nanoscale Cd catalytic sites within a Zn powder matrix. The exsolved Cd establishes strong electronic and orbital coupling with electroactive Zn species, thereby accelerating interfacial electron transfer, strengthening Zn adsorption, and regulating the local ionic‐electric field to favor selective Zn ²⁺ reduction. As a result, the Cd‐Zn electrode achieves an ultralow polarization of 3.8 mV at 1 mA cm ⁻² and a high average Coulombic efficiency of 99.83% at 5 mA cm ⁻² . The Cd‐Zn||I ₂ full cell retains 98% of its initial capacity after 3500 cycles at 2 A g ⁻¹ , while the corresponding 50 mAh pouch cell retains 95% after 200 cycles at 1 A g ⁻¹ . This scalable and generalizable catalytic design provides a viable route toward high‐performance powder‐based Zn anodes for advanced AZIBs.