Porous nitrogen-doped carbon networks derived from orange peel for high-performance supercapacitors

A novel type of porous nitrogen-doped carbon networks derived from a green biomass-waste (orange peel) by integrated carbonization, activation, and nitrogen-doped processes using FeCl3 as activating agent and urea as nitrogen precursor and gasification expander. The porous nitrogen-doped orange peel-based carbon networks (PN-OPC) possessed interconnected porous carbon networks morphology, high specific surface area (1514.2 m2 g−1), reasonable pore size (2.9 nm), and high nitrogen content (about 7.8 wt%). This unique porous network structure and rich nitrogen-dopant leads to fast penetration of electrolyte ions and transmission of electrons, which endow the PN-OPC electrode material with high specific capacitance of 255 F g−1 at current density of 0.5 A g−1 and superior rate capability in 6 mol L−1 KOH aqueous electrolyte. Moreover, the symmetric supercapacitor based on PN-OPC electrode exhibits high specific energy of 16 Wh kg−1 at specific power of 400 W kg−1 operated in the voltage range 0–1.6 V in 0.5 M Li2SO4 aqueous electrolyte, and impressive cyclic stability with 96% after 5000 charge/discharge cycles. Therefore, the present work will open a new strategy to design and fabricate novel porous nitrogen-doped carbon network electrode materials for high-performance supercapacitor.