An Azo Polymer with Abundant Active Sites and Extended Conjugation as a Stable Cathode for High‐Performance Zinc‐Organic Batteries

Abstract

Developing stable cathodes with high capacity and rapid redox kinetics is pivotal for aqueous zinc‐organic batteries (ZOBs). A huge challenge lies in balancing the density of active sites and electronic conductivity of organic cathodes. Herein, an azo polymer from 4,5,9,10‐pyrene‐tetraone (PTAP) possessing high active components and extended conjugated structure was achieved. The extended conjugated system linked by the azo groups facilitates extensive electron delocalization and a low band gap, which endows the PTAP with enhanced electronic conductivity reaching 4.26×10⁻3 S m⁻¹. The azo groups themselves serve as active centers for two‐electron transfer, leading to a significant increase in the density of redox‐active sites and charge storage efficiency. Moreover, strong intramolecular interactions and unique solvation structure bolster the anti‐solubility of PTAP. Consequently, PTAP‐based ZOBs exhibited high reversible capacities and rate performance, delivering 442.45 mAh g⁻¹ at 0.2 A g⁻¹ and maintaining 248.61 mAh g⁻¹ even at 10 A g⁻¹. Additionally, a ZOB showed remarkable long‐term stability after cycling over 900 hours at 5 A g⁻¹. Mechanistic studies further revealed that multi‐step coupling of carbonyl and azo groups accompanied by the Zn2+/H+ dual‐ion insertion is responsible for rapid 12‐electron transfer in PTAP.