Unveiling the Mechanism of Durable Zinc Metal Anodes Enabled by a Low-Concentration Glycerol Electrolyte Additive

Zinc-ion energy storage is emerging as one of the prominent contenders to replace lithium-ion batteries in the future power market. However, challenges arise due to the unstable interface between the zinc anode and electrolyte, leading to issues such as dendrite growth and side reactions that impede the advancement of aqueous zinc-based battery technology. One promising solution to address these challenges is the use of electrolyte additives, nevertheless typically requiring larger volume fractions to achieve significant improvements. In this study, glycerol, a friendly alcohol molecule, is proposed as a low volume concentration of electrolyte additive (10 vol %) that enables remarkably stable Zn anode cycling for over 1500 h at a harsh 5 mAh cm-2 (5 mA cm-2). In comparison, the reference Zn//Zn symmetric cells are disabled after less than 100 h. This performance enhancement at a low additive concentration is attributed to effective morphology regulation and the inhibition of side reactions, as demonstrated through comprehensive experimental analyses and theoretical simulations. Furthermore, the assembled Zn//carbon full cell reveals prolonged cycling life with a slight glycerol additive, illumining the practical prospects of this approach.