Porous Carbons Prepared from Polyacrylonitrile Doped with Graphitic Carbon Nitride or Melamine for Supercapacitor Applications

Abstract

AbstractMelamine and graphitic carbon nitride (g‐C3N4) obtained by thermal condensation of melamine were doped in polyacrylonitrile (PAN) films. Nitrogen‐doped porous carbons were then prepared by pyrolysis of the composite films. Though all the porous carbons had a high nitrogen content of at least 10 %, g‐C3N4 was more efficient than melamine in nitrogen doping. The nitrogen content was elevated with the increase of the amount of each dopant, the highest value of 19.0 % was achieved by g‐3 (porous carbon obtained from the PAN/g‐C3N4 composite film with a mass ratio of 3). Amongst the nitrogen functionalities, pyridinic‐N and pyrrolic‐N held a percentage of at least 80 %. Compared with the carbon materials obtained from melamine doped PAN films, those from g‐C3N4 doped ones exhibited larger surface area and average pore size, and higher pore volume. The difference mainly resulted from the thermostability and size of the dopants. The g‐C3N4 doped materials thus presented more excellent electrochemical properties. The specific capacitance of g‐3 electrode was 135.3 F/g at a current density of 0.5 A/g. Rather than melamine, g‐C3N4 could improve the chemical composition and textural properties of the carbon materials, thus enhancing their supercapacitor performance.