Structural and electrochemical properties of N-doped graphene–graphite composites

This work studied the impact of graphene content and heat treatment on the structural changes and electrical parameters of graphite/N-doped graphene mixtures. Using photoelectron spectroscopy the appearance of two types of carbon-containing phases was detected in the visible range of the N-doped graphene samples synthesized from liquid nitrogen. The following features of the samples were shown: one typical structure of graphene (sp2C–sp2C), two atypical structures (sp3C–N and the C–O bond), and graphene components modified with nitrogen (pyridine–N, pyrrole–N, graphite–N and oxidized N–O). The dependence between the ratio of components in graphite–graphene mixtures and their electrochemical properties was found. The effect of graphite content and heat treatment on the change in the type of conductivity in a graphite–graphene mixture was determined by comparison of resistance and capacitance distribution in the frequency range of 100–900 Hz. The change of the graphite concentration in the graphene–graphite mixture allows governing the type of doping and electrical parameters of the mixtures.