A zwitterionic-type multifunctional electrolyte additive of trigonelline hydrochloride stabilizes zinc anodes for advanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) have garnered worldwide attention owing to their high safety, competitive price, excellent charge storage capacity and environment friendliness. However, the problems of hydrogen evolution , corrosion and dendrite growth lead to capacity degradation and low Coulombic efficiency, hindering the successful realization in practical applications of ZIBs . Herein, an effective and multifunctional electrolyte additive , i.e., trigonelline hydrochloride (Tri), is developed as one of the zwitterion-type additives in ZnSO 4 electrolyte. On the one hand, the Tri molecules weaken the solvation interactions between Zn 2+ and H 2 O, regulating the concentration of Zn 2+ ions. On the other hand, the Tri molecules adsorb on the Zn anode surface and tune the transfer kinetics of Zn 2+ ions, preventing hydrogen evolution reaction (HER) on the anode surface and alleviating dendritic growth and corrosion of Zn foil. Moreover, the lower pH value of electrolytes aroused by Tri can suppress the formation of by-products, such as Zn 4 SO 4 (OH) 6 ·5H 2 O (ZSH) and ZnO. Consequently, the suppressed side reactions, such as HER, corrosion and dendrite formation during Zn plating/stripping process of Zn symmetric battery (Zn||Zn) and full batteries (Zn||LFP and Zn||V 2 O 5 ) significantly enhance cycling life and reversibility after utilizing Tri additive electrolyte. These findings suggest potential avenues for further research into leveraging zwitterion-type additives to enhance the performance of zinc-ion batteries.