A facile template approach to nitrogen-doped hierarchical porous carbon nanospheres from polydopamine for high-performance supercapacitors

Nitrogen-doped hierarchical porous carbon nanospheres (NHPCNs) with mesoscale and microscale pores are reported herein for their application in high-performance supercapacitor electrode materials (SCMs). The NHPCNs were facilely prepared via the carbonization of mesoporous polydopamine nanospheres (MPNSs) fabricated by one-step self-polymerization of dopamine using Pluronic F127 as a soft template. The influence of polymerization and carbonation temperatures on the morphologies, structures, and capacitor performances of the as-prepared NHPCNs was investigated systematically. The specific surface area of the NHPCNs can be achieved as high as 1725 m(2) g(-1), together with a pore volume of 1.85 cm(3) g(-1). Due to their unique structure, the NHPCNs can act as high-performance SCMs and exhibit high charge storage capacity with a high specific capacitance of 433 F g(-1) in 6 M KOH at a current density of 0.5 A g(-1) and excellent stability with 95.7% of the initial capacitance after 10 000 cycles.