Hydrogen bond elimination and nanopore confinement enable oxidized indanthrone for high-performance aqueous zinc...

Organic materials have garnered increasing attention in aqueous zinc-ion batteries (AZIBs) owing to their structural tunability, diversity, and sustainability. Nevertheless, their practical applications in AZIBs cathode remain hindered by challenges including low capacity, short cycle lifespan, and ambiguous ion insertion mechanisms. Herein, we strategically eliminate intramolecular hydrogen bonds in quinone-based organic molecule indanthrone through oxidation method, transforming it into multi-active-site quinone-imine compound oxidized indanthrone (oIDT). Concurrently, oIDT is confined within mesoporous hollow carbon spheres (MHCS) featuring high specific surface area and optimized pore architecture. The precisely designed oxidized indanthrone and mesoporous hollow carbon sphere (oIDT/MHCS) hybrid material achieves high capacity of 294.2 mAh g^-1, excellent rate performance of 194.5 mAh g^-1 at 10 A g^-1, and durable cycle life of 83 % after 20,000 cycles at 10 A g^-1. Such superior performance ascribes to the CN generated after hydrogen bond elimination in oIDT and O⋅⋅⋅Zn⋅⋅⋅N bond formed by synergistic coordination of CN and CO enhances the adsorption of Zn²⁺. Additionally, mesoporous hollow carbon acts as nanoreactor for the coordination of organic molecules with Zn²⁺, and abundant mesopores provide suitable transport channels for electrolyte ion. Combined with density functional theory calculations and ex-situ characterizations, the ion insertion mechanism, interface by-products and final discharge product of cathode material were further investigated. This work provides important insights into the molecular engineering and nanostructure design of high-performance organic cathode in AZIBs.