Salt-assisted pyrolysis of covalent organic frameworks to porous heteroatom-doped carbons for supercapacitive energy storage

Supercapacitors have attracted intensive research interest due to their advantages including longer cycling ability and higher power density. Porous heteroatom-doped carbons (PHCs) have been regarded as a class of promising electrode materials for supercapacitors because of their unique porous, electronic and chemical properties. However, synthesis of PHCs with hierarchical mesoporous/microporous structures and ultra-high porosity and electrochemical performance remains a great research challenge. In this research, two oxygen and nitrogen co-doped PHCs (denoted as ONC-T1s) are prepared via a saltassisted pyrolysis method using covalent organic frameworks (COFs) as the precursor. ONC-T1s show a hierarchical porous structure with an ultra-high specific surface area (up to 3451 m(2) g(-1)). The ONC-T1-850-based supercapacitor exhibits a high specific capacitance of 1711 F g(-1) at 1 A g(1), an ultra-fast charge-discharge rate up to 500 A g(-1) with a specific capacitance of 856 F g(-1), and excellent stability. This work establishes a promising strategy for preparation of PHCs using COFs or other porous organic polymers as precursors and demonstrates the great potential of PHC-based supercapacitors.