Houttuynia-derived nitrogen-doped hierarchically porous carbon for high-performance supercapacitor

Three-dimensional (3D) heteroatom-doped nanostructured carbon materials have gained extensive attention because of their tremendous potential for enhancing supercapacitor performance. Herein, based on a mild carbonization/activation process we successfully developed green/sustainable 3D hierarchically porous nitrogen-doped nanostructure carbon (N–HNC) materials from houttuynia biomass, showing high specific capacitance and high cyclic stability. The as-prepared houttuynia-derived porous carbon material shows a unique flower-like architecture with well-distributed micro/meso pores and a high specific surface area of 2090 m2/g. The assembled supercapacitor based on N–HNC sample shows superior specific capacitance (473.5 F/g at 1 A/g) and remains over 50% of specific capacitance at 20 A/g. The N–HNC based symmetric supercapacitor, constructed with a two-electrode configuration, shows an energy density of 15.99 Wh/kg at 500 W/kg and outstanding capacitance retention of 95.74% even after 10,000 charge-discharge cycles at 10 A/g in an aqueous 6 M KOH electrolyte system. The results highlight the potential of the 3D porous N-doped hierarchical nano-structural carbon materials from houttuynia biomass as candidate electrodes for supercapacitor applications. This study provides an example of using the inherent framework structure of biomass as a precursor to synthesize hierarchically porous nitrogen-doped nanostructure for high-performance supercapacitor applications.