Achieving Stable Zinc Metal Anode Via Polyaniline Interface Regulation of Zn Ion Flux and Desolvation

Aqueous zinc-ion batteries feature high safety, low cost, and relatively high energy density; however, their cycle life is hindered by severe Zn dendrite formation and water-induced parasitic reactions. Herein, a porous polyaniline (PANI) interfacial layer is developed on the surface of Zn metal anode to regulate the transport and deposition of Zn²⁺, achieving an ultra-stable and highly reversible Zn anode. Specifically, the abundant polar groups (-NH- and =N-) in PANI have a strong attraction to H₂O, which can trap and immobilize H₂O molecules around Zn²⁺. Moreover, the protective layer regulates ion flux and deposition behavior of Zn²⁺ through the ion confinement effect. Consequently, the Zn@PANI anode exhibits improved reversible plating/stripping behavior with a low nucleation overpotential (37.9 mV) at 2.0 mA cm^-2 compared to that of bare Zn anode. The MnO₂//Zn@PANI cell demonstrates a high capacity retention of 94.3% after 1000 cycles at 1.0 A g⁻¹. This study lays the foundation for accessible interface engineering and in-depth mechanistic analysis of Zn anode.