New method for N-doped micro/meso porous carbon as electrode material for high-performance supercapacitors

The preparation method of porous carbon traditionally involves many steps and requires inert atmosphere resulting in time-consuming and high-cost. We reported a simple and easy method of N-doped micro/meso porous carbon (NPC) via a one-step carbonization of polyvinylpyrrolidone, melamine and ammonium chloride in air. The influences of PVP mass and carbonization temperature on surface group function, the morphology, microstructure and pore distribution of NPC samples were studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy and surface area analysis. The thermal behavior of NPC was analyzed by thermogravimetric analysis coupled to Fourier transform infrared spectroscopy. Moreover, the electrochemical performances of the as-prepared NPC samples were measured by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The micro/meso pores and high content of pyridine-N and quaternary-N endowed NPC samples with high capacitive performance and long cyclic life. The specific capacitance of the prepared NPC sample could reach as high as 215.9 F g−1 at 1 A g−1 and 89.5 F g−1 even at 10 A g−1. Especially, the symmetric supercapacitor assembled by NPC-3-900 achieved 13.2 W h kg−1 at 350 W kg−1 and excellent cyclic performance (91.4% after 10,000 GCD circles).