Rational construction of hierarchical porous carbon with ultrahigh specific surface area and rich heteroatoms toward high-performance supercapacitors

Favourable pore configuration and active heteroatoms contribute significantly to intrinsic electrochemical performance of carbon materials. Herein, N, S co-doped porous carbons are prepared through a two-step calcination process, in which pre-carbonized chitosan, thiourea and potassium hydroxide are served as carbon source, dopant and activator, respectively. Optimal sample CTK-3 exhibits considerable specific surface area (SSA), remarkable micropore configuration and heteroatom content. Therefore, it exhibits a remarkable specific capacitance (309.4 F g−1 at 0.5 A g−1), cyclic stability (98.7% after 8000 cycles) and rate capability. Moreover, the symmetrical supercapacitors assembled by CTK-3 yields an ultrahigh energy density of 15.6 Wh kg−1, indicating appealing application potential of the N, S co-doped porous carbon.