Constructing zinc-tin alloy interface for highly stable alkaline zinc anode

Abstract

Aqueous alkaline zinc batteries have received widespread attention owing to its higher electrode potential and faster reaction kinetics compared to in mild aqueous electrolyte. However, Zn metal anode in alkaline electrolyte usually suffers more severe corrosion, passivation, and hydrogen evolution reaction. Herein, an interface chemical regulation strategy employs to in-situ construct a Zn-Sn alloy layer during cycling. The K2[Sn(OH)6] has been introduced into the electrolyte as the deposition overpotential of Zn and Sn in alkaline electrolyte is approximate leading to their simultaneously plating. The Zn-Sn alloy layer not only prevents Zn anode corrosion and suppresses the dendrite growth but also promotes the reaction kinetics. Therefore, the Zn||Zn cell exhibits a long life of 400 h in alkaline electrolyte about 20 times of that in without K2[Sn(OH)6] electrolyte. Moreover, the N-NCP@PQx||Zn full cell displays a superior cycle performance of 4000 cycles with 93% capacity retention at 2 A/g.