Covalent Organic Framework Derived Oxygen/Sulfur-Doped Porous Carbon for Robust High-Capacitance Symmetric Supercapacitors.

Heteroatom-doped porous carbons (HPCs) have been considered promising electrode materials for supercapacitors due to their improvement of energy density by providing extra pseudocapacity. Covalent organic frameworks (COFs) are obtaining great importance in energy storage because of their designable structure and versatile functionality. Herein, we designed and fabricated oxygen and sulfur dual-doped covalent organic framework (COF) derived HPCs with very high heteroatoms content (up to 25.76 atom%) via a facile coupling reaction. The optimized HPCs exhibit a porous structure with high specific surface area (up to 2835 m² g^-1) along with a high specific capacitance (430 F g^-1 at 0.5 A g^-1), excellent capacitance retention (96.9 %), and high coulombic efficiency (98.5 %) after 10000 cycles at 5 A g^-1. As electrodes for aqueous symmetric supercapacitors, the HPCs exhibits a high energy density of 60 Wh kg^-1 at a 250 W kg^-1 power density, excellent cycling stability of capacity retention (82.2 %) and a high coulombic efficiency (92.3 %) after 10000 cycles at 10 A g^-1, indicating attractive application potential in chemical energy storage. This work establishes a promising strategy for preparation of high heteroatom content HPCs using COFs and demonstrates great potential for energy storage/conversion devices.