Zwitterionic Polymer Micelles Enable Interface Regulation for Long-Life Aqueous Zinc–Iodine Batteries

Aqueous zinc–iodine batteries are promising for safe and low-cost energy storage, yet their practical performance is hindered by zinc dendrite growth and polyiodide shuttling. Herein, we propose an interfacial regulation strategy based on self-assembled polymer micelles. We designed a zwitterionic polymer containing imidazole-sulfonate and acrylamide units that spontaneously forms nanoscale micelles in ZnSO4 electrolyte and adsorb onto zinc electrode surfaces, constructing a multifunctional interface layer. This layer reconstructs Zn2+ solvation, reduces water activity, and enables uniform zinc deposition, thus suppressing dendrites and corrosion. Meanwhile, multivalent interactions within the micelles immobilize polyiodide species, mitigating the shuttle effect. As a result, Zn||Zn cells achieve stable cycling for over 5000 h, and Zn–I2 pouch cells retain 93.3% capacity after 100 cycles at high iodine loading (33.06 mg cm–2). This work demonstrates polymer micelle self-assembly as an effective strategy for interfacial regulation in zinc–iodine batteries.