Oxide-doped hierarchically porous carbon for high-performance supercapacitor

Abstract

Suffering from a relatively low energy density, carbon-based supercapacitors are restricted in the practical applications for green energy. However, heteroatom-doped hierarchically porous carbon materials (HPCs) can deliver prominent electrochemical performance as an electrode material. Herein, we report a simple two-step method for the synthesis of oxide-doped HPC with an ultra-high specific surface area of 3043.3 m² g−1. In a three-electrode system, the specific capacitance of the oxide-doped HPC is as high as 375 F g−1 at 1 A g−1. Also, an aqueous symmetric supercapacitor (AS) assembled with the oxide-doped HPC achieves a high specific capacitance of 353 F g−1 at 1 A g−1 and excellent rate performance of 84.9% capacitance retention with current density up to10 A g−1. Most importantly, the energy density of the AS in the 3 M KOH solution can reach up to 17.7 Wh kg−1 at a power density of 600 W kg−1. In 1 M Na2SO4 solution, the specific capacitance of the AS shows no decay after 5000 cycles at 5 A g−1. These results reveal that the as-prepared oxide-doped HPC has great potential as an electrode material to realize remarkable electrochemical performance in supercapacitors.