Simplified synthesis of N, S co-doped ordered mesoporous carbon cathode via a one-step impregnation technique for superior Zn-ion hybrid supercapacitors

Aqueous zinc-ion hybrid supercapacitors (ZHSCs) are emerging as promising energy storage devices due to their safety and low cost. The development of cathode materials with superior performance has become a focal point in ZHSC research. Herein, N, S co-doped ordered mesoporous carbons (N, S-OMC) were synthesized via a one-step impregnation of pyrrole and 2-thiophenemethanol into the mesopores of silica templates. The effect of the pyrrole-to-2-thiophenemethanol feed ratio on the microstructure and electrochemical performance of N, S-OMC was examined. The optimal electrochemical performance of N, S-OMC-25 can be attributed to the synergistic effects of well-controlled N and S doping levels, high content of pyridine N, numerous defect sites, good conductivity, ordered mesoporous channels, and a large surface area, all of which provide numerous accessible active sites for charge storage and enhanced electrochemical kinetics in ZHSCs. The N, S-OMC-25-based ZHSCs device demonstrated a high specific capacity (269 ± 1 F/g), high energy density (82 Wh/kg), and outstanding cyclic stability, retaining 95 % capacity after 10,000 cycles in 1 M ZnSO₄ and 95 % after 60,000 cycles in 3 M Zn(CF₃SO₃)₂. This work simplifies the preparation of N, S-OMC via the template method and introduces N, S-OMC carbon materials for use in aqueous ZHSCs devices.