Ag x Zn y Protective Coatings with Selective Zn 2+ /H + Binding Enable Reversible Zn Anodes.

Zinc (Zn) metal anodes suffer from the dendrite growth and hydrogen evolution reaction (HER) in classical aqueous electrolytes, which severely limit their lifespan. We propose a rational design of Ag x Zn y protective coatings with selective binding to Zn 2+ against H + to simultaneously regulate the Zn growth pattern and the HER kinetics. We further demonstrate that by tuning the composition of the Ag x Zn y coating the Zn deposition behavior can be readily tuned from the conventional plating/stripping (on Zn-AgZn 3 coating) to alloying/dealloying (on Ag-AgZn coating), resulting in precise control of the Zn growth pattern. Moreover, the synergy of Ag and Zn further suppresses the competitive HER. As a result, the modified Zn anodes possess a significantly enhanced lifespan. This work provides a new strategy for enhancing the stability of Zn and potentially other metal anodes by precisely manipulating the binding strength of protons and metal charge carriers in aqueous batteries.