Nitrogen-Doped Porous Carbon Prepared from Urea Formaldehyde Resins by Template Carbonization Method for Supercapacitors

Through a simple and convenient template carbonization method, nitrogen-doped porous carbon has been successfully achieved by heating urea formaldehyde (UF) resin and magnesium citrate at 800 °C, where the magnesium citrate serves as a template. The mass ratio between the UF resin and magnesium citrate plays a crucial impact on the surface areas, pore structures, and the correlative capacitive behaviors of the final porous carbons, denoted as samples UF-Mg-1:1, -1:3, and -1:5. All present porous carbons exhibited amorphous features with low graphitization degrees. Sample UF-Mg-1:3 displayed the best capacitive performance with a large specific capacitance of 239.7 F g–1 at a current density of 0.5 A g–1 and a high energy density of 33.3 Wh kg–1 at a power density of 0.25 kW kg–1. More importantly, it exhibited a high capacitance retention of 94.4% after 5000 charge/discharge cycles, clearly indicating good cycling durability.