Rational Design of an Interfacial Bilayer for Aqueous Dendrite-Free Zinc Anodes.

Aqueous zinc (Zn) metal batteries have been widely studied on account of their evident advantages including low cost, good safety, and high energy density. However, problems associted with the Zn anode, such as dendrite formation and corrosion reaction, severely impact the safety and electrochemical performance of a battery. In this work, a bilayer design is constructed on the Zn anode surface to overcome these stubborn issues. A copper nanosheet layer together with a graphene oxide coating constitutes this artificial composite layer, enabling chemical modulation of uniform deposition of the ion flux and simultaneously eliminating the parasitic reaction by a physical barrier. Electrochemical characterization reveals the evident reduced ion nucleation barrier during plating, and the clean Zn anode surface after cycling indicates the inhibition of the corrosion reaction with the reliable shield. As a result, with this dendrite-free modified Zn electrode, both the symmetric cell and the full cell demonstrate remarkable rate and lifespan properties. A long-term cycling life of 2000 h can be realized in the symmetric cell. A high-rate property of 15 A g -1 and better capacity retention are also achieved in the full cell after being coupled with a Na x V 2 O 5 nH 2 O cathode.