Zn-Alloying Sites with Self-Adsorbed Molecular Crowding Layer as a Stable Interfacial Structure of Zn Electrodes

Rechargeableaqueous zinc (Zn) metal batteries (ZMBs) have gainedtremendous attention because of their intrinsic safety and low cost.However, the lifespan of ZMBs is seriously limited by severe Zn dendriticgrowth in aqueous electrolytes. Despite the feasibility of Zn depositionregulation by introducing Zn-alloying sites at the Zn plating surface,the activity of the Zn-alloying sites can be seriously reduced byside reactions in the aqueous environment. Here, we propose a facilebut efficacious strategy to reinforce the activity of the Zn-alloyingsites by introducing a low quantity of polar organic additive in theelectrolyte that can be self-adsorbed on the Zn-alloying sites toform a molecular crowding layer against the parasitic water reductionduring Zn deposition. As a consequence, stable cycling of the Zn anodecan be maintained at such a multifunctional interfacial structure,arising from the synergism between the seeded low-overpotential Zndeposition on the stabilized Zn-alloying sites and a Zn2+ redistributing feature of the self-adsorbed molecular crowding layer.The interfacial design principle here can be widely employed due tothe great variety of Zn-alloy and polar organic materials and potentiallybe applied to improve the performance of other aqueous metal batteries.

Automated summary

Rechargeable aqueous zinc metal batteries have received great attention due to their safety and low cost. However, the growth of zinc dendrites in aqueous electrolytes severely limits the lifespan of these batteries. In this study, a strategy was proposed to enhance the activity of zinc-alloying sites by introducing a small amount of polar organic additive in the electrolyte, forming a molecular crowding layer to prevent parasitic water reduction during zinc deposition. This multifunctional interfacial structure allows stable cycling of the zinc anode and can potentially improve the performance of other aqueous metal batteries.