Amphiphilic Dodecanoic Monolayer Protects Zinc Anode from Water-Involved Side Reactions

Aqueous zinc ion batteries (AZIBs) have gained unprecedented attention based on their high volumetric energy density, low price, and excellent eco-friendness. However, the persistent challenges posed by zinc dendrite formation and severe side reactions hinder their application in industry. Therefore, we introduce the in situ self-assembly of dodecanoic acid (DA) into an ultrathin amphiphilic layer on the zinc surface, which can suppress the troublesome side reactions and promote uniform deposition on the Zn anode. The carboxyl group of the DA molecular head is bonded onto the zinc anode surface, and the hydrocarbon tail is arranged vertically on the zinc foil surface to form a hydrophobic layer that effectively isolates the active zinc from the aqueous electrolyte. Accordingly, the symmetric cell of the DA-modified Zn (DA@Zn) achieved stable long cycle performance over 3000 h at an areal current density of 2 mA cm–2 and a specific areal capacity of 1 mAh cm–2. Furthermore, DA@Zn anodes also exhibited enhanced rate performance and cycling stability in full cells compared with bare zinc anodes. The introduction of the amphipathic DA layer onto the zinc anode provides new insights into the realization of stable zinc metal anodes.