Dual nitrogen sources co-doped mesoporous carbon with ultrahigh rate capability for high-performance supercapacitors

Nitrogen-doped ordered mesoporous carbon (N-OMC) was synthesized through evaporation induced self-assembly (EISA) technique by using pyrrole and carbamide as N sources. The obtained N-OMC has high-ordered 2D-hexagonal mesostructures with uniform pore size and high specific surface area. When pyrrole and carbamide were simultaneously employed as N sources, the sample shows higher subtotal percentage of pyridinic and pyrrolic N, leading to better electrochemical performance. As-prepared N-OMC with dual N sources (N-12 -OMC-1) possesses an ultra-high specific capacitance of 310 F g(-1) at the current density of 1.0 A g(-1) and remains 245 F g(-1) (nearly 80% of its capacitance at 1.0 A g(-1)) at 20 A g(-1), achieving both high rate capability and high specific capacitance. N-12-OMC-1 based symmetrical supercapacitor demonstrates the highest energy density of 17.8 Wh kg(-1) at a power density of 225 W kg(-1) and maintains 12.2 Wh kg(-1) at a very high output power density of 13500 W kg(-1) in 1 M Na2SO4 electrolyte. Moreover, the N-12-OMC-1 based symmetrical supercapacitor exhibits an excellent long-term electrochemical stability with 96.2% capacitance retention and 97% coulombic efficiency after 5000 cycles. Outstanding performances of N-12-OMC-1 make it a potential candidate for supercapacitor applications. (C) 2020 Elsevier B.V. All rights reserved.