Bifunctional Covalent Organic Framework for Efficient Iodine Capture and High-Performance Energy Storage

Herein, we report a nitrogen-rich triazine-based covalent organic framework (TPATFB-COF), synthesized via the condensation of 5,5',5″-(1,3,5-triazine-2,4,6-triyl)tris(pyridin-2-amine) (TPA) and 1,3,5-triformylbenzene (TFB). The resulting TPATFB-COF, enriched with nitrogen sites, enables dual functionality in iodine capture and supercapacitor applications by facilitating strong adsorption interactions and efficient charge transport. The exceptional thermal and chemical stability of the COF is attributed to robust covalent linkages. The π-electron-rich arenes and nitrogen centers enable strong iodine adsorption, while its π-conjugated framework and redox-active sites facilitate efficient charge transport for high-performance energy storage. The exceptional iodine uptake by TPATFB-COF across various phases (5.9 g g^-1: vapor, 75 °C; 2.28 g g^-1: vapor, 25 °C; 1.6 g g^-1: organic, 25 °C and 3.9 g g^-1: aqueous, 25 °C), with excellent recyclability and retention, was observed. In energy storage, it achieves maximum specific capacitances of 455 F g^-1 (GCD, 5 A g^-1) and 402 F g^-1 (CV, 5 mV s^-1), delivering an energy density of 63.19 Wh kg^-1 and a power density of 2500 W kg^-1. In the symmetric configuration, it maintains 90% capacitance retention over 10,000 cycles with a high Coulombic efficiency of 95%. These results highlight TPATFB-COF as a promising material for sustainable iodine capture and high-performance energy storage. The dual functional behavior of COF offers promising avenues for addressing challenges related to nuclear waste management and the growing demand for high-performance supercapacitors.