Multifunctional tin layer enabled long-life and stable anode for aqueous zinc-ion batteries

Aqueous zinc-ion battery is a low-cost, non-toxic, and high-safety energy storage system, which has received extensive attention in recent years. However, the Zn anode with high theoretical capacity often suffers from severe corrosion and dendrite growth during the Zn plating/stripping process, leading to severe polarization and eventually short circuits. These knotty problems severely impede further practical applications of Zn-based batteries. Herein, a robust and homogeneous metallic tin (Sn) coating is in situ built on the surface of Zn to form Zn|Sn by a facile chemical vapor deposition method to enhance reaction reversibility. The as-prepared Sn coating not only affords more robust nucleation sites of Zn and higher hydrogen evolution reaction potential, but also effectively decreases the nucleation overpotential of Zn. Accordingly, the symmetric cells with Zn|Sn anode can stably maintain an extremely low-voltage hysteresis (50 mV) in a 500 h of plating/stripping cycles. Even at a high current density of 50 mA cm−2, the symmetric Zn|Sn cell still can operate well for 50 h. Moreover, this stable Zn|Sn anode also enables a full Zn-ion battery with outstanding rate and cyclic stability.