A Multifunctional Molecule Based on Rapid Adsorption Enables Highly Reversible Zinc Anodes via Steric...

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 Zn²⁺ to reconstruct the solvation shell of Zn²⁺ 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 H₂O 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||MnO₂ 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.