Chemical diffusion and ionic conductivity in nonstoichiometric nanocrystalline superionic NaxCu1.75S (x = 0.1, 0.15, 0.2, 0.25) materials

Thermal and electrical properties of nanocrystalline superionic NaxCu1.75S (x=0.1, 0.15, 0.2, 25) compounds

“…Ionic conductivity in sodium-doped copper sulfide Na 0.2 Cu 1.8 S was recently reported in the study [24], in which it was noted that doping with sodium did not significantly affect the ionic conductivity of copper sulfide: the ionic conductivity increase exponentially up 1.5 to 2.3 S cm −1 in the temperature range up 630 to 690 K. Observed values are comparable with the level of the ionic conductivity of the binary copper sulfide. Results of studies of chemical diffusion and ionic conductivity in Na x Cu 1.75 S (x=0.1, 0.15, 0.2, 25) nonstoichiometric nanocrystalline superionic materials were reported recently by K. Kuterbekov et al [25]. High values of the coefficient of conjugated chemical diffusion of cations and electronic holes (1.1 • 10 −3 and 1.65 • 10 −3 cm 2 /s at 410 • C) were observed in the Na 0.10 Cu 1.75 S and Na 0.20 Cu 1.75 S electron-ionic conductors.…”

“…The synthesis of the Na x Cu 2-x-y S powders was carried out by reaction of CuCl with Na 2 S • 9H 2 O in a melt of NaOH and KOH hydroxides. Details of synthesis procedure are described in our earlier paper [25].…”

“…In the superionic phases the measured values of the total ionic conductivity are 2.8, 1.5 and 2.0 S/cm for Na 0.10 Cu 1.75 S , Na 0.15 Cu 1.75 S and Na 0.20 Cu 1.75 S at 410 • C respectively. Thus, it was conclude in [25] that insertion of sodium to copper sulfide not lead to worse of high ionic conductivity in the superionic phase. In this article, we present the results of the studies of thermal properties of nanocrystalline superionic Na x Cu 1.75 S (x=0.1, 0.15, 0.2, 25) compositions, and preliminary results of Na 0.1 Cu 1.75 S using as energy stored cathode material in Na-ion half-cell with NaPF 6 electrolyte and Na disc anode.…”

Investigation of thermoelectric properties of nanocrystalline copper chalcogenides

“…However, it was not possible to obtain simultaneously high values of the Seebeck coefficient for the non-stoichiometric composition studied by us. Since the thermoelectric, electrical and thermal properties of chalcogenides are very sensitive to non-stoichiometry of the composition, it is possible that higher indicators of thermoelectric efficiency can be achieved by selecting the optimal degree of non-stoichiometry of the composition [10][11][12]. Вестник Карагандинского университета М.М.…”

Investigation of the temperature and precursors concentration dependence of the formation of ZnSe quantum dots

“…To date, metallic chalcogenide quantum dots (QDs) are attracting increasing interest from scientists, because of their special optical properties. They are mainly used in such areas as: light-emitting diodes (LED), nanolasers, fluorescent probes for biomarkation [1][2][3]. A potential problem of QDs based on Cd, Pb and Hg is their toxicity.…”