Sn Alloying to Inhibit Hydrogen Evolution of Zn Metal Anode in Rechargeable Aqueous Batteries

The detrimental hydrogen evolution side reaction is one of the major issues hindering the commercialization of Zn metal anode in high-safety and low-cost rechargeable aqueous batteries. Herein, the authors present a Sn alloying approach to effectively inhibit the hydrogen evolution and dendrite growth of the Zn metal anode. Through in situ monitoring of the hydrogen production during repeated plating/stripping tests, it is quantitatively demonstrated that the hydrogen evolution of alloy electrode with appropriate Sn amount is only half of that of pure Zn electrode. Furthermore, the Sn alloying allows for favorable Zn nucleation sites, lowering the Zn nucleation energy barrier and promoting more uniform Zn deposition. The Zn-Sn alloy electrode offers much-improved plating/stripping cycling, that is, over 240 h at 5 mA cm(-2) and 35.2% depth of discharge. This work provides a practically viable strategy to stabilize Zn metal electrode in rechargeable aqueous batteries.