The rampant "top-growth" dendrites, hydrogen evolution reaction (HER), and zinc (Zn) self-corrosion severely impede the further development of rechargeable aqueous zinc ion batteries. To address these challenges, a novel double-layer gradient coating consisting of a zincophilic Sn inner layer and an organic polymer outer layer (OSA/PAM@Sn) is constructed on the surface of the Zn anode. The organic outer layer, composed of cross-linked oxidized sodium alginate and polyacrylamide (OSA/PAM), not only serves as a physical barrier to isolate active water but also accelerates Zn