Structure and electrochemical performance of nitrogen-containing nanoporous carbon from diphenylcarbazide via a template carbonization route

In this work, a simple template carbonization method has been developed to produce nitrogen-containing nanoporous carbon from diphenylcarbazide, using Mg(OH)2 as hard template. The carbonization temperature has a crucial role in determining the carbon structure. The carbon-3:1-800 sample obtained with the mass ratio of diphenylcarbazide and Mg(OH)2 as 3:1 at 800 °C exhibits the optimum pore structure as well as the resultant best electrochemical performance. It has a large BET surface area of 1538.0 m2 g−1, high pore volume of 3.48 cm3 g−1, and hierarchical pore size distribution. As a result, it delivers superior electrochemical behaviors in a three-electrode system using 6 mol L−1 KOH as electrolyte, whose specific capacitance calculated from galvanostatic charge-discharge curve can reach up to 517.4 F g−1 at a current density of 1 A g−1, which is much larger than most of the nanocarbons ever reported in the literature. The carbon-3:1-800 sample also exhibits good cycling stability within 10000 cycles. Comparatively, the electrochemical test has also been carried out in a two-electrode system using [EMIm]BF4/AN as electrolyte. More importantly, the operation temperatures of 25/50/80 °C can greatly broaden the application scope of nanoporous carbon in the supercapacitor.