Ag<sub><i>x</i></sub>Zn<sub><i>y</i></sub> Protective Coatings with Selective Zn<sup>2+</sup>/H<sup>+</sup> Binding Enable Reversible Zn Anodes.

Zheng, Jiaxian; Liu, Xin; Zheng, Yuguo; Gandi, Appala Naidu; Kuai, Xiaoxiao; Wang, Zhoucheng; Zhu, Yunpei; Zhuang, Zechao et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

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<sub><i>x</i></sub>Zn<sub><i>y</i></sub> protective coatings with selective binding to Zn<sup>2+</sup> against H<sup>+</sup> to simultaneously regulate the Zn growth pattern and the HER kinetics. We further demonstrate that by tuning the composition of the Ag<sub><i>x</i></sub>Zn<sub><i>y</i></sub> coating the Zn deposition behavior can be readily tuned from the conventional plating/stripping (on Zn-AgZn<sub>3</sub> 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.