New binary carbon composites (GDY-NCNTs and GDY-CNTs) with a three-dimensional porous structure, which are synthesized by an in situ growth method, are adopted in this article. The GDY-NCNTs composites exhibit excellent specific capacitance performance (679 F g-1, 2 mV s-1, 139% increase compared to GDY-CNTs) and good cycling stability (with a capacity retention rate of up to 116% after 10000 cycles). The three-dimensional porous structure not only promotes ion transfer and increases the effective specific surface area to improve its specific capacitance performance but also adapts to the volume expansion and contraction during the charging and discharging process to improve its cycling stability. The presence of nitrogen doping in the carbon nanotubes of GDY-NCNTs increases the surface defects of the composites, provides more electrochemical points, and improves the surface wettability of the composites, further improving the electrochemical performance of the composites.
Keywords: 3D nanocomposite; carbon nanotube; graphdiyne; in situ growth; nitrogen doping; supercapacitor.