Toward dendrite-free and anti-corrosion Zn anodes by regulating a bismuth-based energizer

Abstract

Aqueous rechargeable zinc metal batteries display high theoretical capacity along with economical effectiveness, environmental benignity and high safety. However, dendritic growth and chemical corrosion at the Zn anodes limit their widespread applications. Here, we construct a Zn/Bi electrode via in-situ growth of a Bi-based energizer upon Zn metal surface using a replacement reaction. Experimental and theoretical calculations reveal that the Bi-based energizer composed of metallic Bi and ZnBi alloy contributes to Zn plating/stripping due to strong adsorption energy and fast ion transport rates. The resultant Zn/Bi electrode not only circumvents Zn dendrite growth but also improves Zn anode anti-corrosion performance. Specifically, the corrosion current of the Zn/Bi electrode is reduced by 90% compared to bare Zn. Impressively, an ultra-low overpotential of 12 ​mV and stable cycling for 4000 ​h are achieved in a Zn/Bi symmetric cell. A Zn–Cu/Bi asymmetric cell displays a cycle life of 1000 cycles, with an average Coulombic efficiency as high as 99.6%. In addition, an assembled Zn/Bi-activated carbon hybrid capacitor exhibits a stable life of more than 50,000 cycles, an energy density of 64 ​Wh kg−1, and a power density of 7 ​kW ​kg−1. The capacity retention rate of a Zn/Bi–MnO2 full cell is improved by over 150% compared to a Zn–MnO2 cell without the Bi-based energizer. Our findings open a new arena for the industrialization of Zn metal batteries for large-scale energy storage applications.