Molecular Customization of Anode‐Electrolyte Interfaces for Enhanced Stability and Reversibility in Aqueous Zinc‐Carbon Capacitors

Abstract Aqueous zinc‐carbon capacitors display application potential in green power and high‐end equipment owing to their high security, large power and sustainability. The water‐rich zinc anode‐electrolyte interface (AEI) and disordered zinc‐ion diffusion are the culprits triggering corrosion reactions and dendrite growth, threatening the sustainability of aqueous zinc‐carbon capacitors. Herein, a polyfunctional biomolecular, vitamin B 6 , is introduced into the traditional aqueous electrolyte for customizing the functional AEI and fine‐regulating the interfacial coordination environment of zinc ions. Specifically, the preferential anchoring of pyridine nitrogen enables trace vitamin (2.0 g L −1 ) to construct a robust AEI and suppress corrosion reactions. The hydroxyl function zone provides high‐octane guidance for zinc‐ion diffusion at the AEI, resulting in flat zinc (002) oriented growth. Consequently, the Zn//Zn symmetrical cell features an ultrahigh cumulative capacity of 4.0 Ah cm −2 under 34 % depth of discharge. The vitamin‐optimized zinc‐carbon capacitor features extended operational lifetimes exceeding 8 months (200 thousand cycles at 5.0 A g −1 ), and demonstrates a high areal capacity of averaging 0.68 mAh cm −2 and exceptional durability over 2000 hours at 1.0 A g −1 under a high discharge depth of zinc anode (averaging 11.6 %). This work offers valuable insights into sustainable and cost‐effective zinc‐carbon capacitors.