Electronically Conjugated Multifunctional Covalent Triazine Framework for Unprecedented CO 2 Selectivity and High‐Power Flexible Supercapacitor

Multifunctional porous carbon materials are the key to a clean, safe, and sustainable working environment and energy storage devices because they can be reused, recycled, and repurposed. Here, unprecedented electronically conjugated nanoporous covalent triazine frameworks (CTFs) containing 4‐(Dicyanomethylene)‐2,6‐dimethyl‐4 H ‐pyran (DDP) surface functionalities is designed for the selective adsorption of carbon dioxide (CO 2 ) over nitrogen (N 2 ) gas under ambient conditions; materials are repurposed to form an active electrode material for the fabrication of dimensionally stable high energy density solid‐state flexible supercapacitors (SFSC). The functional 4 H ‐pyran unit of DDP in ‐resonance with the triazine frameworks enriches the overall surface polarities for improved selective gas adsorption and serves as charge storage and/or discharge pockets during electrochemical switching. Consequently, DDP‐based CTFs show an optimum CO 2 adsorption of 154.0 mg g −1 and record CO 2 /N 2 selectivity of 185.8 at 273 K under atmospheric pressure. In addition, an eminent energy density of 147.5 Wh kg −1 at a power density of 750 W kg −1 is accomplished with the fabricated SFSC. This material demonstrates no loss of capacitive performance under mechanical bending of 140° for long cycles and can power a commercial light emitting diode easily.