N-doped hierarchical porous carbon derived from corncobs by molten salt method for high-performance supercapacitors

The use of biomass-derived carbon in supercapacitors is widespread due to the advantages of low price and environmentally friendly. However, these materials often exhibit limitations regarding specific capacity and cycle characteristics. Therefore, in this study, N-doped hierarchical porous carbon (NPC) was obtained by onestep LiCl/KCl molten salt carbonization activation using biomass waste corncobs as the carbon precursor and urea as an N doping medium. By modifying the ratio of molten salt to precursor, NPC-10 exhibits an optimal microstructure including specific surface area and pore characteristics. Furthermore, the suitable degree and type of N doping provide additional reactive active sites for energy storage. The combination of N doping and hierarchical porous improves the energy storage capacity of the NPC. The NPC-10 has a specific capacity of 278.2 F g(-1) at 1 A g(-1) and maintains 169.5 F g(-1) at 100 A g(-1). This study offers a novel approach to the synthesis of hierarchical porous carbon materials derived from biomass for the storing energy in supercapacitors.