Triazole-boosted dual-structured covalent triazine frameworks for ultra-stable high-energy and -power density aqueous supercapacitors and notable selective CO2 capture

Abstract

Dual-structured nitrogen-rich covalent triazine frameworks (BMTz-CTFs) were ionothermally synthesized using a new 3D benzonitrile monomer functionalized with 1,2,3-triazole acting as a multi-tasking entity boosting electrochemical and gas adsorption properties. A high surface area up to 1557 m² g⁻¹, a large pore volume up to 1.13 cc g⁻¹ with mixed micropores and narrow mesopores, and optimized blend of partially graphitic carbon structures embedded with redox-active N-species synergistically endow BMTz-CTFs with superior CO₂ capture performance, high CO₂/N₂ selectivity, and enhanced electrochemical charge storage and discharge kinetics. BMTz-CTF600 demonstrated notable CO₂ adsorption capacities of 5.77 (273 K, 1 bar) and 2.54 mmol g⁻¹ (273 K, 0.15 bar), with an impressive CO₂/N₂ (15 : 85) IAST selectivity of 82. Repurposed into a two-electrode symmetric aqueous supercapacitor assembly of 2.4 V, they delivered a capacitance up to 225.7 F g⁻¹, alongside record energy (44.7 W h kg⁻¹) and power densities (5526.8 W kg⁻¹). At 10 A g⁻¹, the device retained 95.6% of its initial capacitance after 10 000 cycles and maintained 94.2% capacity after repeated 10 000 cycles, even after seven months. The flexible device showed stable capacitive performance under mechanical bending, variable temperature (−10 °C to 80 °C), and humidity (40–90%).