Simple CVD growth of P-doped graphitic hallow carbon spheres for high-voltage (2.0\xa0V) aqueous symmetric supercapacitor

Abstract

Doping of heteroatom into well-structured mesoporous carbon architecture can significantly augment the capacitive performance. In this work, we report P-doped graphitic hollow carbon spheres (P-GHCS) grown over Fe-KIT-6 through the in situ approach using the catalytic CVD technique. The obtained P-GHCS possesses a relatively high surface area with uniform mesoporous structure, good graphitization with tunable P-doping contents. The highly favorable structure and desirable heteroatom doping were taken into account to evaluate the P-GHCS as a modified electrode material towards high-performance supercapacitor. The optimized P-GHCS-800 sample exhibits superior specific capacitance (Csp) 321 F g−1 at 0.2 A g−1 with outstanding cycling stability with 2.9% loss of its initial capacitance after 2000 cycles in 6 M KOH electrolyte background in the three-electrode computerized system. More importantly, the fabricated P-GHCS-800 symmetric supercapacitor device can withstand at a wide potential width of 2.0 V, together with remarkable cyclic stability (89.09%) after 2000 cycles at a current density of 1 A g−1 in aqueous 1 M Na2SO4 as electrolyte providing a relatively high energy density of 10.83 Wh kg−1 with a power density of 222.78 W kg−1. Additionally, we demonstrated the single symmetric supercapacitor cell which provided sufficient energy to turn on a red LED of 20 mW and emit light over a certain period of time opens up possible realistic applications.