Properties of N-doped graphitized nano diamond electrode materials for supercapacitors

The mixture of melamine and graphitized nano diamond(GND)was used to prepare super capacitor materials with high energy density and high cycle performance.The raw material was treated at high temperature in nitrogen atmosphere to prepare the core-shell nanocomposites of N-doped graphene(N-GND).Raman spectroscopy and X-ray diffraction analysis showed that the addition of N atoms into the graphite layer increased the defects in the graphite layer to a certain extent without changing its crystal structure.TEM analysis showed that N-doping caused the curl shape of graphite layer around GND.The electrochemical performance of N-GND electrode was tested.Results showed that the specific capacitance of the electrode was 206.7 F/g at 5 mV/s.In the constant-current charge-discharge test of symmetrical two-electrode system, the specific capacitance of N-GND was 198.7 F/g at 0.4 A/g.The specific capacitance attenuated only 4.23% even after 2 000 cycles of CV, indicating excellent cyclic stability of the electrode at 50 mV/s.N-GND, as the electrode material of a new supercapacitor, had good conductivity due to its graphene shell and high thermal and chemical stability for the GND core.It could also avoid the stacking problem of traditional graphene and construct controllable mesoporous channels.In addition, N-doping would improve the capacitance performance.