Synthesis and design of hypercrosslinked porous organic frameworks containing tetraphenylpyrazine unit for high-performance supercapacitor

Human society faces significant environmental challenges due to the rapid production and consumption of fossil fuels. Therefore, developing effective and environmentally friendly methods of generating and storing energy is essential. Hypercrosslinked polymers (HPPs) have become increasingly popular due to their diverse preparation methods, simple functionalization, large specific surface area, low cost, mild reaction conditions, high chemical and thermal stability, and small size. We synthesized two hypercrosslinked porous organic polymers using Friedel-Crafts reactions of 2,3,5,6-tetraphenyl pyrazine (Pyra) with 4,4′-bis(chloromethyl)biphenyl (BP), and dimethoxymethane (DDM), resulting in Pyra-BP-HPP and Pyra-DDM-HPP, respectively. The chemical structures and thermal stability of these polymers were confirmed through solid-state ¹³C NMR, FTIR, and TGA. The surface area of Pyra-BP-HPP and Pyra-DDM-HPP was determined to be 984 and 435 m² g⁻¹, respectively, with micro and mesoporous structures present. Pyra-BP-HPP displayed a high specific capacitance of 94 F g⁻¹ at 1 A g⁻¹, with a capacity retention of 95% after 2000 cycles, which can be attributed to its larger surface area, microporosity, and abundance of electron-rich phenyl rings when compared to Pyra-DDM-HPP.