One-step template carbonization-activation synthesis of nitrogen-doped hierarchical porous carbon for supercapacitors

Nitrogen-doped hierarchical porous carbon with a high-specific surface area has been successfully synthesized via a one-step template carbonization-activation of nicotinic acid. The mass ratio of Mg (OH)2 and KOH to carbon precursor plays a crucial role in controlling porosity and nitrogen content of the product. Our optimized sample shows a hierarchical porous structure with a high surface area (2608 m2 g−1), large pore volume (4.0 cm3 g−1), and reasonable incorporation of nitrogen (2.2%). In addition, the electrode made using this optimized material shows a maximum specific capacitance of 282 F g−1 at a current density of 1 A g−1 and outstanding rate performance (64% capacitance retention at 20 A g−1). An assembled symmetric capacitor using this material displays a maximum energy density of 21.5 Wh kg−1 and 95% retention over 5000 cycles at 5 A g−1 at 25 °C. Moreover, our facile, simple, and efficient method of fabrication paves the way large-scale application of these porous carbon materials for high-performance supercapacitors.