Hydrothermal synthesis of 3D hierarchical ordered porous carbon from yam biowastes for enhanced supercapacitor performance

3D hierarchical ordered porous carbon with outstanding electrochemical performance is synthesized by a low-cost and facile hydrothermal carbonization and chemical activation process through adopting biomass yam wastes as raw material. [Display omitted] •A facile hydrothermal carbonization process is proposed to fabricate O-N co-doped 3D hierarchical ordered porous carbon.•The hierarchical ordered porous carbon shows a super high specific surface area of 1952 m2 g−1 and excellent conductivity.•The carbon material exhibits an outstanding gravimetric capacitance of 556.0 F g−1 at a current density of 0.5 A g−1. Through simple treatment of biowastes to obtain carbon materials with hierarchical ordered porous structure and prominent specific capacity has received increasing attention. Herein, novel uniform three-dimensional (3D) hierarchical porous carbon was generated by a low-cost and facile hydrothermal carbonization and chemical activation process from yam biowastes. Specially, the derived uniform 3D hierarchical carbon demonstrates an ultra-high specific capacity of 556.0 F·g−1 at 0.5 A·g−1 and a superior cycle stability with a capacitance retention of 94.7 % after 10,000 cycles at 10 A·g−1 in 6 M KOH. Moreover, the assembled symmetrical supercapacitor provides an outstanding energy density of 45.5 Wh·kg−1 if the specific power was 200.0 W·kg−1 in 1 M Na2SO4 electrolyte. The encouraging results presented herein make the 3D hierarchical ordered porous carbon immensely promising for supercapacitors with good property.