Carbonyl-Enhanced Small-Molecule Cathodes Enable Ultrahigh-Rate Aqueous Zinc-Ion Batteries

Organic cathode materials continue to attract significant research interest in aqueous zinc-ion batteries (AZIBs) owing to their eco-friendliness and molecular design flexibility. However, these advantages are counterbalanced by inadequate cycling stability, unsatisfactory rate capability, and compromised low-temperature tolerance, with these limitations being particularly acute in small organic molecules. This work reports an organic small molecule, the conjugated quinone derivative benzo[g]indeno[1,2-<i>b</i>]quinoxaline-6,11,13-trione (BIQT), developed through strategic heteroatomic substitution as a high-performance cathode material for AZIBs. The molecular design simultaneously enhances structural stability and promotes extended electron delocalization, effectively mitigating electrolyte dissolution while facilitating accelerated charge transfer kinetics. These properties endow Zn//BIQT batteries with exceptional electrochemical performance, delivering a high specific capacity of 383.9 mAh g^–1 at 0.1 A g^–1, sustaining 85.0 mAh g^–1 under an ultrahigh current density of 60 A g^–1, maintaining extended cycling stability over 10,000 cycles, and operating reliably at −20 °C with a 280.1 mAh g^–1 capacity. Combined density functional theory (DFT) calculations and electrochemical characterization reveal that the capacity of BIQT originates from Zn²⁺/H⁺ cointercalation storage behavior involving a five-electron transfer process. This molecular architecture demonstrates a viable design strategy for high-performance organic cathodes in advanced AZIBs.