Molecular Engineering of π‐Conjugated C═O/C═N Cathode for Ultrastable Organic Zinc‐Ion Batteries

ABSTRACT Organic materials with high capacity and sustainability are widely used in aqueous zinc‐ion batteries (ZIBs), yet organic materials with multi‐redox centers and stable structures are seldom reported. Herein, we design a novel π‐conjugated organic molecule with twelve C═O and C═N active sites, BDQDT (Bisdipyrido[4,3‐a:3’,4’‐c]quinoxaline[3,2‐a:2’,3’‐h]‐11,24‐dihydrophenazine‐10,12,23,25‐tetraone), enabling strong electron delocalization, reinforced π–π stacking, and suppressed dissolution. As a result, BDQDT ZIBs exhibit excellent rate capability with 84.0 mAh g −1 at 20 A g −1 and outstanding cycling stability after 12 000 cycles. Besides, In situ characterizations combined with DFT calculations confirm Zn 2+ /H + co‐insertion mechanism. The optimized discharged structure is identified as BDQDT‐1Zn‐10H, binding from one BDQDT molecule with one zinc ion and ten protons. Impressively, flexible Zn‐ion device of BDQDT maintains stable properties under various mechanical deformations, and could power a humidity sensor. Prospectively, this work would build molecular engineering strategies for high‐capacity and stable organic ZIBs.