Fast Kinetics Enabled by Ion Enrichment Layer for Dendrite-Free Zinc Anode.

Aqueous zinc-ion batteries (AZIBs) are considered a promising choice for energy storage devices owing to the excellent safety and favorable capacity of the Zn anode. However, the uncontrolled dendrite growth of Zn anode severely constrains the practical applications of AZIBs. Herein, a novel ion enrichment layer of CuS is designed and constructed on the Zn foil surface to achieve dendrite-free Zn anode. This CuS with appropriate Zn affinity and hollow architecture exhibits ion enriching characteristics. Furthermore, CuS@Zn anode can significantly reduce de-solvation barriers of hydrated Zn²⁺, promoting Zn²⁺ migration and minimizing nucleation overpotential. Benefiting from the above results, the Zn deposition kinetics are effectively improved. As expected, the CuS@Zn anode exhibits significantly improved Zn plating/stripping reversibility for 1000 h at 1 mA cm^-2 and 900 h at 5 mA cm^-2 _. Furthermore, the assembled CuS@Zn||MnO₂ full battery also exhibits superior rate performance and cycling stability. This work provides a feasible method to achieve uniform and dense Zn deposition for the stabilization of Zn anode.