Coupling Active Site Evolution and p-π Conjugation in Organodisulfide for High-Performance Aqueous Zinc Batteries

Organodisulfides have recently emerged as a promising cathode material for aqueous zinc batteries (AZBs) due to their advantages such as high specific capacity, tunable electrochemical activity, and low cost. The reversible cleavage and formation of sulfur–sulfur (S–S) bonds during discharge and charge promote the coordination and decoordination of zinc ions. However, traditional organodisulfides as electrode materials suffer from issues such as limited active sites, low output voltage, and structural instability. Herein, guided by the concept of active site evolution, we strategically employed 2,2′-dithiobis(pyridine-1-oxide) (DPDO) featuring optimized redox-active sites and tunable electron distribution as cathode materials for AZBs. Theoretical calculations and experimental results collectively demonstrate that the N → O group in DPDO undergoes reversible redox reaction and enhances the Zn2+/H+ storage capacity. And the electron-withdrawing effect of the N → O group reduces the electron cloud density of the S–S bond, resulting in a higher discharge voltage for DPDO. Moreover, the p-π conjugation induced by the interaction between p-electrons of the O and π-electrons of the pyridine ring extends the molecular conjugation system and promotes electron delocalization. To further address the inherent electronic insulation and easy solubility of organic small molecules, DPDO is confined within metal–organic framework-derived hierarchical porous carbon (HPC). The Zn||DPDO/HPC battery delivers a high discharge capacity of 328.9 mAh g–1 at 0.1 A g–1, maintaining 229.5 mAh g–1 at a current density of 10 A g–1. The battery achieves a capacity of 207.4 mAh g–1 after 500 charge and discharge cycles, retaining 87.1% of the initial capacity, and exhibits a superior energy density of 301.3 Wh kg–1. This work provides critical insights for designing high-capacity and long-lasting organosulfur cathodes for advanced aqueous zinc batteries.