Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

Abstract

The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257m2g−1 and Nonlocal density functional theory (NLDFT) mesopore size of 14.61nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO3 solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314Fg−1 at a current density of 0.5Ag−1 was achieved in 2M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20Ag−1 and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2Ag−1.