Intramolecular electronic modulation enabled high-capacity Zn²⁺/H⁺ co-insertion in benzoquinone-fused anhydride...

Organic materials have attracted considerable attention in rechargeable aqueous zinc-ion batteries (AZIBs) due to their sustainability and structural tunability. However, the electrochemical performance of existing organic electrodes is severely constrained by limited redox-active sites, high solubility and short conjugated backbones. Herein, a conjugated N-heterocyclic anhydride-based framework, benzoquinone-fused dianhydride (NTBQ), was constructed via solid-state condensation to enable highly reversible Zn²⁺/H⁺ storage. The strategic integration of C=O groups triggers intramolecular electrostatic potential reconstruction and activates adjacent C=N sites, enabling fast and thermodynamically spontaneous multi-electron Zn²⁺/H⁺ co-insertion. The rational structural design endows the NTBQ cathode with a remarkable initial discharge specific capacity of 434.6 mAh g^-1 at 0.05 A g^-1 and excellent rate capability. Moreover, the extended π-electron delocalization significantly strengthens intermolecular π-π interactions, enhancing the dissolution resistance of NTBQ in aqueous electrolytes and affording long-lasting cycling durability (88.1% retention after 10,000 cycles at 10 A g^-1). Systematic mechanistic studies demonstrate that the superior electrochemical performance originates from the synergistic redox chemistry of C=O/C=N dual-active centers within the anhydride-based skeleton. These findings demonstrate that intramolecular electronic modulation can effectively evoke multi-electron redox activity, providing an effective avenue for designing high-performance organic cathodes toward advanced AZIBs.