Phthalonitrile-derived hierarchical porous carbon through synergistic KOH/KCl activation for high-performance supercapacitor electrodes

Abstract

Hierarchical porous carbon (HPC) materials hold immense promise for advancing high-performance supercapacitors. However, the development of straightforward and sustainable synthetic routes remains a formidable challenge. This work employs a facile strategy combining low-temperature carbonization with the synergistic effects of chemical activation and salt templating, utilizing phthalonitrile monomer (RPH) as precursors to synthesize N-enriched hierarchical porous carbon. The optimized RKC-1 sample features an advantageous pore size distribution, a large specific surface area of 2079 m² g⁻¹, a N-doping loading of 1.86 %, and a moderate degree of graphitization. The RKC-1 electrode demonstrates a notable level of specific capacitance of 394 F g⁻¹ at 1 A g⁻¹. Notably, in a two-electrode system at 5 A g⁻¹, after undergoing 10,000 cycles, the RKC-1 electrode maintains a capacitance retention rate of 80.34 % and achieves a Coulombic efficiency of 99.24 %. These results underscore that the synthesized RPH-based porous carbon demonstrates promising potential for practical applications in advanced energy storage systems.