Biomimetic robust polymeric interphase facilitating stable Zn metal anode

•A biomimetic polydopamine (PDA) interphase is introduced via a Cu2+-assisted minute-level in-situ polymerization method.•The polymeric interphase reduce the nucleation energy barrier, facilitating homogenous dendrite-free deposition.•DEMS analysis demonstrates that the amount of H2 release is substantially restricted, ensuring a long-term cycling stability.•The modified Zn@PDA anode endows the pouch-type cell with impressive lifespan of 500 cycles at 0.5 A g–1. Rampant dendrite growth and hydrogen evolution reaction of Zn anode severely hinder the practical application of aqueous zinc-ion batteries (AZIBs). Traditional surface modifying layers tend to have distinct interface with the Zn plate, which readily results in detachment and failure of the modification under repeated cycling. Herein, inspired by mussel adhesive proteins, a uniform and dense polydopamine (PDA) layer is introduced on Zn surface by a Cu2+-assisted minute-level in-situ polymerization method. The robust polymeric interphase can improve the zincophilicity and wettability of Zn surface, reducing the energy barrier for Zn nucleation to facilitate homogenous dendrite-free deposition. Importantly, the PDA layer can promote the desolvation process of hydrated Zn2+ by abundant –NH2 and –OH groups, and effectively suppress side reactions associated with H2O, such as hydrogen evolution reaction, and Zn corrosion, ensuring the long-term cycling stability of the Zn anode. As a result, the PDA modified Zn anode achieves prolonged cycling stability of 840 h under high deposition capacity of 5 mAh cm–2 and current density of 5mA cm–2. Moreover, the pouch-type cell based on the PDA modified Zn anode delivers impressive reversible lifespan for 500 cycles at 0.5 A g–1, demonstrating the potential application prospect for this biomimetic interphase in AZIBs.