A Multifunctional Molecule Based on Rapid Adsorption Enables Highly Reversible Zinc Anodes via Steric Hindrance‐Desolvation Effect

The electrolyte–electrode interface critically governs the performance of aqueous zinc‐ion batteries (AZIBs), where electrolyte‐mediated interfacial regulation is pivotal. Herein, 5‐benzimidazolecarboxylic acid (BCA) is introduced as a novel trace electrolyte additive for highly reversible, dendrite‐free zinc anodes. The BCA additive containing both imidazole and carboxyl functional groups can not only provide strong coordination with Zn 2+ to reconstruct the solvation shell of Zn 2+ and regulate the zinc ion flux by improving the bulk steric hindrance, but also rapidly adsorb onto the Zn anode to form a multifunctional molecular protective layer, reducing the contact of H 2 O by increasing interfacial steric hindrance, while simultaneously promoting desolvation of the zinc ions from the solvent. Consequently, BCA‐enhanced symmetric cells achieve exceptional cycling stability even at high current densities, operating over 5000 h (5 mA cm −2 ) and exceeding 1200 h (10 mA cm −2 ), while asymmetric cells deliver an ultralong lifespan exceeding 3400 h with a 99.84% average coulombic efficiency. Additionally, the Zn||MnO 2 cell retains 70.7% capacity after 1000 cycles (1C). And a high‐mass‐loading pouch battery exhibits stable cycling and powers a 3 V LED. This study provides profound insights into interfacial engineering for high‐performance AZIBs.