De-Passivation and Surface Crystal Plane Reconstruction via Chemical Polishing for Highly Reversible Zinc Anodes

Despite the widespread adoption of Zn anodes for aqueous energy storage, the presence of an inherent passivation layer and the polycrystalline interface of commercial Zn foil consistently lead to non-uniform electrodeposition, undermining stability and practicality. Herein, the study introduces a chemically polished Zn metal anode (CP-Zn) fabricated via a simple immersion method. This "chemically polishing" process can effectively remove the interfacial passivation layer (de-passivation), providing ample active sites for plating/stripping and ensuring the uniformly distributed electric field and Zn²⁺ ion flux. Additionally, selective etching during chemical polishing exposes more (002) crystal planes, promoting homogeneous and smooth zinc deposition while suppressing related side reactions. Demonstrated by CP-Zn anode, the symmetric cell exhibits stable cycling over 4600 h at 1 mA cm^-2 and 240 h at 50% depth of discharge (DOD), with a CP-Zn||VO₂ full cell maintaining ≈75.3% capacity retention over 1000 cycles at 3 A g^-1. This chemically polishing strategy presents a promising avenue for advancing the commercialization of aqueous zinc-ion batteries.