AgxZny Protective Coatings with Selective Zn2+/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_xZn_y protective coatings with selective binding to Zn²⁺ against H⁺ to simultaneously regulate the Zn growth pattern and the HER kinetics. We further demonstrate that by tuning the composition of the Ag_xZn_y coating the Zn deposition behavior can be readily tuned from the conventional plating/stripping (on Zn-AgZn₃ 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.