Fishbone-derived N-doped hierarchical porous carbon as an electrode material for supercapacitor

A cost-effective and sustainable approach has been developed to synthesize N-doped carbon material from fishbone waste via a one-step carbonization without an addition of chemical activator as a catalyst. The carbonization temperature can be optimized so that a favorable layered structure is achieved in 3D-flake nitrogen-doped hierarchical porous carbon (NPC). NPC-850 (NPC that was carbonized at 850 °C) not only has a high specific surface area of up to 1337 m 2 g −1 , but is also richly doped with heteroatoms (N and O content of 5.8 and 7.99 at.%, respectively). NPC-850 also exhibits an excellent electrochemical supercapacitor (SC) performance, i.e., a maximum specific capacitance of 476 F g −1 in a three-electrode system and 354 F g −1 in a symmetrical SC (both in a 1 M H 2 SO 4 ), and a maximum energy density of 21.2 Wh kg −1 in a symmetrical SC (in a 1 M TEABF 4 /AN). Moreover, NPC-850 can achieve high cycling stability, with 90.9% retaining of the original capacitance after 10,000 continuous cycles at a 1 A g −1 current density. Such an outstanding performance suggests that our facile and scalable synthesis technique is effective to prepare porous carbon from biomass for electrochemical energy storage. • Fishbone was carbonized to produce N-doped carbon without chemical activation. • NPC-850 has a high specific surface area of up to 1337 m 2 g −1 . • As supercapacitor electrode, NPC-850 can achieve specific capacitance of 476 F g −1 . • NPC-850 retains ∼91% of original capacitance after 10,000 continuous cycles.