Dendrite Suppression by Anode HCl Treatment in Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) are the most perspective energy storage system because of their low cost, safety, abundant zinc reserves, and environmental friendliness. However, Zn dendrite growth remains the main reason that limits the life span of ZIBs. Recently researchers have proposed various methods to alleviate or inhibit dendrite growth, such as electrolyte additives, modified anodes, alternative cathode materials, etc. However, relatively little research has been done on the zinc structure itself. Herein, a quick and simple hydrochloric acid (HCl) pretreatment of zinc foil before electrochemical operation resulted in a significant reduction of zinc dendrites and an extension of the cycle life of the cell compared to raw Zn foil. By combining ex-situ SEM and ex-situ AFM, it was proved that the initial structural defects of zinc foil determine the subsequent plating/stripping morphology. Appropriate defects on zinc foil can prolong battery cycling life. It is also applicable in flexible batteries with hydrogel as electrolyte. This study provides a simple method for wider commercial application of ZIBs in the future and provides new ideas for the study of zinc dendrite growth.