Long-Life Zn Anode Enabled with Complexing Ability of a Benign Electrolyte Additive

Abstract

The development of aqueous zinc ion batteries (AZIBs) is hindered by several problems, including Zn dendrite/corrosion, side reactions, and hydrogen evolution reaction (HER). Herein, trisodium citrate (NaCit) additive is introduced into the ZnSO 4 electrolyte to guide the preferred Zn(002) crystal plane growth, while the Cit − is preferentially adsorbed on the active sites to suppress the HER and Zn corrosion, thus achieving uniform Zn deposition without dendrites. The stable cycle life can reach 2000 h at 0.25 mA cm −2 /0.05 mAh cm −2 . The density functional theory simulations further indicate that the parallely placed Cit − has the lowest adsorption energy (−6.617 eV); it can form a weak interaction with Zn metal to promote the growth of (002) crystal planes. Furthermore, the assembled Zn//polyaniline full cell and pouch cell both exhibit good rate performance and long cycling stability. The complexation and dissolubilization effects of the NaCit additive provide a means for designing high-performance AZIBs.