3D Leaf-Like Copper-Zinc Alloy Enables Dendrite-Free Zinc Anode for Ultra-Long Life Aqueous Zinc Batteries.

Abstract

Metallic zinc exhibits immense potential as an anode material for aqueous rechargeable zinc batteries due to its high theoretical capacity, low redox potential, and inherent safety. However, practical applications are hindered by dendrite formation and poor cycling stability. Herein, a facile substitution reaction method is presented to fabricate a 3D leaf-like Cu@Zn composite anode. This unique architecture, featuring a 3D network of leaf-like Cu on a Zn foil surface, significantly reduces nucleation overpotential and facilitates uniform Zn plating/stripping, effectively suppressing dendrite growth. Notably, an alloy layer of CuZn5 forms in situ on the 3D Cu layer during cycling. DFT calculations reveal that this CuZn5 alloy possesses a lower Zn binding energy compared to both Cu and Zn metal, further promoting Zn plating/stripping and enhancing electrochemical kinetics. Consequently, the symmetric Cu@Zn electrode exhibits remarkable cycling stability, surpassing 1300 h at 0.5mA cm-2 with negligible dendrite formation. Furthermore, full cells comprising Cu@Zn||VO2 exhibit superior capacity and rate performance compared to bare Zn anodes. This work provides a promising strategy for constructing highly stable and efficient Zn anodes for next-generation aqueous zinc batteries.