Empowering High-Performance Aqueous Zinc-Ion Batteries with Low-Cost Zinc Acetate Electrolytes

Aqueous zinc-ion batteries (AZIBs) suffer from poor cycling stability of zinc anodes due to side reactions and dendrite growth. This work investigates the application of a 1 M zinc acetate (ZOA) electrolyte in aqueous AZIBs. Structural analysis reveals that the solvation structure in the ZOA electrolyte involves a monovalent complex, Zn(OAc)+·4H2O, and a neutral, hexacoordinate complex, Zn(OAc)2·2H2O. Cycling performance in Zn//Zn symmetric cells using the ZOA electrolyte revealed a stable lifespan of over 650 h at 2 mA cm–2, obviously better than 1 M ZnSO4 electrolyte. Morphological characterization further confirms the zinc dendrite alleviation effect in the ZOA electrolyte. When paired with a bipolar poly(1,5-diaminonaphthalene) (1,5-PDAN) cathode in a full-cell configuration, the battery delivers a specific capacity of 124 mAh g–1 at 1 A g–1 and retained 55% after 6000 cycles, demonstrating superb cycling stability. Kinetics analysis indicates that the energy storage mechanism of the 1,5-PDAN cathode in the ZOA electrolyte is predominantly pseudocapacitive. The result highlights the compatibility of the ZOA electrolyte with the organic bipolar cathode.