Enabling highly reversible Zn anode via an interfacial preferentially adsorbed additive containing nucleophilic groups

The cyclability and reversibility of aqueous zinc-ion batteries (AZIBs) are severely hampered by the safety concerns arising from the Zn dendrite growth. Therefore, a stable anode with inhibited dendrites and side reactions is crucial for AZIBs. Herein, we utilized methyl acetoacetate (MA) as an additive to prevent dendrite growth and enable highly reversible Zn anodes. Benefiting from the nucleophilic groups (carbonyl groups) in MA, MA molecules can preferentially adsorb on the anode/electrolyte interface (AEI), forming a molecular protective layer. Such MA layers can not only regulate the migration and deposition of zinc ions, but also inhibit side reactions induced by the decomposition of free H2O molecules at AEI. Therefore, the symmetric cell with the addition of MA achieves a long-term cycling stability of 1,500 h at 2 mA cm-2 with a capacity of 2 mAh cm-2. In addition, the Zn//NVO full cell using MA-contained electrolyte demonstrates a high specific capacity (138.4 mAh g-1) with an outstanding capacity retention (92.8% after 600 cycles) at 1 A g-1. This work provides a principle for the use of ester-based additives with nucleophilic groups to suppress Zn dendrite growth for highly durable zinc metal anodes.