Scalable Interfacial Modification of Zn Anode for Aqueous Rechargeable Batteries with Improved Capacity and without Hydrogen Evolution

The Zn anode in rechargeable aqueous Zn-ion battery (AZIBs) suffers from hydrogen gas evolution and dendrite growth, which are critical issues making the current AZIB technology immature. Here, these issues are efficiently tackled by forming an amorphous Zn 1-x Se x protective layer over the Zn foil surface through a simple chemical bath reaction process. The anti-corrosion performance of the Zn anode in aqueous electrolyte is greatly improved, and the Zn@Zn 1-x Se x symmetric cell exhibits notable rate performance and long cycle life of 4500 h after being tested at 1 mA cm −2 and 1 mAh cm −2 . Also, the use of Zn@Zn 1-x Se x leads to a larger Zn 2+ transference number, compared to that that using bare Zn anode. When combined with a MnO 2 -based cathode, the button-type full cell using Zn@Zn 1-x Se x exhibits higher capacity and much longer cycle life, compared to the counterpart using bare Zn anode. It is found that the in situ formation of an amorphous ZnO nanosheet network induced by the amorphous Zn 1-x Se x overlayer plays a key role in improving the Zn anode performance. Pouch cells using high-mass-loading MnO 2 cathode and as-prepared Zn anode are made to demonstrate the hydrogen evolution inhibition and some practical applications.