Multifunctional additive biphenyl-4,4'-dicarboxylic acid enables highperformance aqueous zinc-ion batteries

Abstract

The practical application of aqueous zinc-ion batteries is hindered by issues such as dendrite growth and side reactions on the zinc anode. To address these challenges, this study employs biphenyl-4,4'-dicarboxylic acid (BDA) as an electrolyte additive. Research indicates that BDA molecules initially form an ordered adsorption layer through the interaction of their dicarboxylate functional groups with the biphenyl backbone, which subsequently decomposes during electrochemical cycling to construct an organic-inorganic hybrid solid electrolyte interphase (SEI) layer. This SEI layer effectively suppresses hydrogen evolution reaction and corrosion, promotes uniform zinc deposition, and thereby significantly enhances the reversibility and cycling stability of the battery. Experimental results demonstrate that the electrolyte with 0.01 M BDA enables Zn||Zn symmetric cells to cycle stably for 1200 hours under the condition of 1 mA cm -2 and 1 mAh cm -2 . The Zn||Cu half-cell achieves an average Coulombic efficiency of 99.53 % after 2000 cycles at 1 mA cm -2 and 0.5 mAh cm -2 . Furthermore, the Zn||MnO2 full-cell maintains a capacity retention rate as high as 83.3 % after 500 cycles at a current density of 1 A g -1 .This study provides an effective electrolyte design strategy for developing high-performance aqueous zinc-ion batteries.Although the aforementioned carboxylic acid-based additives show promise in modulating zinc deposition behavior, their practical application still faces common challenges. The introduction of high molecular weight or high viscosity additives is