Hexaazatriphenylene–Quinone Covalent Organic Polymers as a Platform for Stable and High-Performance Supercapacitors

Abstract Developing high-performance supercapacitors requires an optimal balance of capacitance, energy, and power density together with long-term cycling stability. Here, we report a family of heteroatom-doped, spin-active, and redox-active hexaazatriphenylene–quinone covalent organic polymers (COPs) prepared through complementary mechanochemical and solution-phase syntheses. These materials exhibit chemical robustness under acidic conditions and strong pseudocapacitive activity arising from delocalized spin centers and quinone redox sites. Among them, COP-2 displays the most favorable electrochemical characteristics, achieving an areal capacitance of up to 6214 mF/cm2 (863 F/g) and an unprecedented energy density of 1.91 mWh/cm2 (266 Wh/kg) at 1 mA/cm2 in symmetric two-electrode devices. The material also demonstrates high-rate capability with a maximum power density of 51.4 mW/cm2 (7139 W/kg) and stable cycling performance, retaining 82.1% capacitance after 50,000 cycles. Mechanistic studies combining spectroscopy, electrochemical analysis, and electronic structure simulations highlight the interplay of redox activity and spin delocalization in governing charge storage. These results establish a molecular-to-device design framework for developing spin-active porous polymers as advanced energy storage materials.