Ultralow Concentration Zwitterionic Additives Enable Rapid Adsorption Equilibrium Promoting Long‐Life Aqueous Zinc‐Ion Battery

Abstract Aqueous zinc‐ion batteries (AZIBs) face challenges in practical applications due to unstable electrode‐electrolyte interfaces and zinc dendrite growth. This study introduces an ultra‐low concentration (5 mmol L⁻¹) zwitterionic additive, Pyridinium‐1‐Propane‐3‐sulfonate (PPS), to reconstruct the electric double layer (EDL) and regulate zinc surface reactions. Compared with structurally similar ionic additive N‐Butylsulfonicpyridinium (BSO₃Py) and imidazole‐based zwitterionic additive 3‐(1‐Methyl‐1H‐imidazol‐3‐ium‐3‐yl) propane‐1‐sulfonate (MPS), PPS exhibits superior parallel adsorption on zinc. Its dynamic adaptation to Zn²⁺ deposition achieves rapid adsorption equilibrium, optimizing zinc active site utilization. Sulfonic acid groups form a robust interfacial layer through intermolecular interactions, while the hydrophobic pyridine ring blocks water/sulfate contact. Symmetric batteries with PPS achieved 700 hours of cycling at 20 mA cm⁻² and cumulative plating capacity exceeding 7000 mAh, alongside 99.81% Coulombic efficiency at 5 mA cm⁻². Zn‐VO₂ full batteries retained 247.46 mAh g⁻¹ after 1200 cycles at 5 A g⁻¹. This interfacial engineering strategy provides a scalable solution for stable AZIBs.