Electronically Conjugated Multifunctional Covalent Triazine Framework for Unprecedented CO₂ Selectivity and High‐Power Flexible Supercapacitor

Abstract 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‐4H‐pyran (DDP) surface functionalities is designed for the selective adsorption of carbon dioxide (CO₂) over nitrogen (N₂) 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 4H‐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 CO₂ adsorption of 154.0 mg g⁻¹ and record CO₂/N₂ 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.