N‐Doped Hierarchical Porous Carbon with Open‐Ended Structure for High‐Performance Supercapacitors

Abstract

AbstractN‐doped hierarchical porous carbon with an open‐ended nanostructures were prepared through activating hollow carbon spheres (HCS), which were synthesized by using the self‐assembled amphiphilic block copolymer polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) as template and pyrrole as carbon and nitrogen source. Through chemical activation with KOH, the original close‐ended HCS became open‐ended nanostructures (denoted as A‐HCS). This unique structure possesses several important properties as electrode for application in supercapacitors: (a) large surface area (1583 m2/g) and pore volume (3.82 cm3/g), (b) hierarchical porous carbon with small size (<100 nm) and thin curved walls (thickness <20 nm), (c) high N content (6.73 at%). Compared with the close‐ended HCS, the open‐ended A‐HCS exhibits better performance. The A‐HCS electrode presents a high specific capacitance (284 F/g at 0.2 A/g), good rate capability (70 % retention as the current density increased from 0.2 to 30 A/g), and superior cycling stability (96 % retention after 5000 cycles at 10 A/g). These results demonstrate that the N‐doped hierarchical porous carbon material with open‐ended nanostructure represents an alternative promising candidate as an efficient electrode material for supercapacitors.