ИСТИНА

Surface properties of original and spark plasma sintered (SPS) materials (carbon nanotubes, carbon nanoflakes and there nitrogen-substituted derivatives) which can be used as supercapacitors electrodes were studied by liquid nitrogen adsorption, real vapours sorption, Raman spectroscopy and XPS. It was shown that SPS treatment allow to increase the density of the samples up to 1.8 g/cm3 and deduce the macroporosity. At the same time it force to elimination of the oxygen-containing functional groups, which are not suitable for supercapacitors with non-aqueous electrolytes. It was shown that avaliable for electrolyte surface area for the materials under discussion differs from the value, obtained by liquid nitrogen adsorption and depends on the size of the molecules and specific interaction between adsorbent and adsorbate. The isosteric heats of sorption for all the media were calculated as well. The data collected for water, ethanol, acetonitrile, benzene, 1-methylimidasole show both physical adsorption and chemisorption. The mean pore diameter distribution calculated from nitrogen adsorption by DFT shows the reduction of total pore volume in carbon nanoflakes pellets while for nanotubes total pore volume does not differ dramatically from those for non-compacted samples. The HRTEM, thermal analysis and Raman spectroscopy data demonstrate the structural change: the increase of density and thickness of nanoshells stack, formation of interparticle bonds between nanotubes.