Eucalyptus derived heteroatom-doped hierarchical porous carbons as electrode materials in supercapacitors

Carbon-based supercapacitors have aroused ever-increasing attention in the energy storage field due to high conductivity, chemical stability, and large surface area of the investigated carbon active materials. Herein, eucalyptus-derived nitrogen/oxygen doped hierarchical porous carbons (NHPCs) are prepared by the synergistic action of the ZnCl₂ activation and the NH₄Cl blowing. They feature superiorities such as high specific surface area, rational porosity, and sufficient N/O doping. These excellent physicochemical characteristics endow them excellent electrochemical performances in supercapacitors: 359 F g^-1 at 0.5 A g^-1 in a three-electrode system and 234 F g^-1 at 0.5 A g^-1 in a two-electrode system, and a high energy density of 48 Wh kg^-1 at a power density of 750 W kg^-1 accompanied by high durability of 92% capacitance retention through 10,000 cycles test at a high current density of 10 A g^-1 in an organic electrolyte. This low-cost and facile strategy provides a novel route to transform biomass into high value-added electrode materials in energy storage fields.