Preparation and characterization of carbonaceous materials containing nitrogen as electrochemical capacitor

Carbonaceous materials containing nitrogen (C/N materials) were prepared by a pyrolysis of 2,3,6,7-tetracyano-1,4,5,8-tetraazanaphthalene (CAN). A C/N material prepared by the pyrolysis of CAN at 1070 K (CAN-1070 K) had a C/N atomic ratio of 3.0 and a non-crystalline carbonaceous structure with a BET surface area of 880 m2 g−1. The material CAN-1070 K showed large capacitances of 160–180 F g−1 and 110–120 F cm−3 in case of current density of 10 mA cm−2 (2 A g−1) by using three-electrode cell in 1 M H2SO4 aqueous solution, in comparison with that of activated carbon (160 F g−1 and 55 F cm−3) having BET surface area of 2300 m2 g−1. ESCA study indicated that pyridinic and quarternary nitrogen atoms existed in the C/N materials, which could result in producing a pseudo-capacitance in addition to the electric double layer capacitance. Also introduction of nitrogen into the carbonaceous material could enhance the wettability of material, which might also improve the capacitance.