Journal of Vasyl Stefanyk Precarpathian National University

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L.S Kaykan, I.M. Gasyuk, V.V. Ugorchuk, J.S. Kaykan, M.Y. Sichka

ELECTRIC PROPERTIES OF Mg-SUBSTITUTED LITHIUM IRON SPINEL

Journal of Vasyl Stefanyk Precarpathian National University, 1 (1), pp. 9-15, 2014, ISSN: 2311-0155

: Complex impedances of sintered polycrystalline Li0.5Fe2.5xMgxO4 (х = 0.0, 0.1, 0.3, 0.6, 0.8, 1.0) ferrite in the frequency range of 0.01 Hz to 100 kHz were measured at several temperatures in the range of 295-723 K. The complex-plane impedance spectra indicate that the material can be represented by a two-layer leaky capacitor which corresponds to the bulk and the grain boundary phenomena at high and low frequencies respectively. The dependence of impedance and conductivity and dielectric properties on temperature and frequency are discussed.

@article{23110155-101,
title = {ELECTRIC PROPERTIES OF Mg-SUBSTITUTED LITHIUM IRON SPINEL},
author = {L.S  Kaykan and I.M.  Gasyuk and V.V.  Ugorchuk and J.S.  Kaykan and M.Y.  Sichka},
url = {http://journals.pu.if.ua/index.php/jpnu/article/view/252/218},
issn = {2311-0155},
year  = {2014},
date = {03/02/2014},
journal = {Journal of Vasyl Stefanyk Precarpathian National University},
volume = {1},
number = {1},
pages = {9-15},
abstract = {: Complex impedances of sintered polycrystalline
Li0.5Fe2.5xMgxO4
(х = 0.0, 0.1, 0.3, 0.6,
0.8, 1.0) ferrite in the frequency range of 0.01 Hz to 100 kHz were measured at several temperatures
in the range of 295-723 K. The complex-plane impedance spectra indicate that the material can be
represented by a two-layer leaky capacitor which corresponds to the bulk and the grain boundary
phenomena at high and low frequencies respectively. The dependence of impedance and
conductivity and dielectric properties on temperature and frequency are discussed.},
keywords = {ferrite, complex impedance, dielectric constant, dielectric losses, polarization.},
tppubtype = {article},
tpstatus = {published},
}

B.K. Ostafiychuk, I.M. Budzulyak, B.I. Rachiy, L.O. Shyyko, R.P. Lisovsky, N.Ya. Ivanichok, V.M. Vashchynsky

THE IMPACT OF THE SURFACE MORPHOLOGY ON ENERGY CHARACTERISTICS OF NANOPOROUS CARBON MATERIAL

Journal of Vasyl Stefanyk Precarpathian National University, 1 (1), pp. 17-25, 2014, ISSN: 2311-0155

The impact of nanoporous carbon material (PCM) morphology on its electrochemical behavior in aqueous electrolyte has been studied. The optimum concentration of aqueous lithium sulfate which provides the maximum specific energy characteristics of capacitor-type systems C/Li2SO4/C is determined. Capacitive parameters of electrochemical capacitors (EC) in aqueous solutions of lithium, sodium and potassium sulfate which have different molar ratio have been studied by comparative analysis. Cyclic voltammograms at different scan rates show that the PCM capacitive behavior in three electrolytes increases in the following order Li2SO4<Na2SO4<K2SO4. This improvement could be a result of increasing the movement speed of hydrated ions in the volume of electrolyte and in the internal pores of PCM in the order Li+<Na+<K+ . The obtained results give valuable information for the study of new hybrid supercapacitors.

@article{23110155-102,
title = {THE IMPACT OF THE SURFACE MORPHOLOGY ON ENERGY CHARACTERISTICS OF NANOPOROUS CARBON MATERIAL},
author = {B.K.  Ostafiychuk and I.M.  Budzulyak and B.I.  Rachiy and L.O.  Shyyko and R.P.  Lisovsky and N.Ya.  Ivanichok and V.M.  Vashchynsky},
url = {http://journals.pu.if.ua/index.php/jpnu/article/view/253/228},
issn = {2311-0155},
year  = {2014},
date = {03/03/2014},
journal = {Journal of Vasyl Stefanyk Precarpathian National University},
volume = {1},
number = {1},
pages = {17-25},
abstract = {The impact of nanoporous carbon material (PCM) morphology on its electrochemical
behavior in aqueous electrolyte has been studied. The optimum concentration of aqueous lithium
sulfate which provides the maximum specific energy characteristics of capacitor-type systems
C/Li2SO4/C is determined. Capacitive parameters of electrochemical capacitors (EC) in aqueous solutions
of lithium, sodium and potassium sulfate which have different molar ratio have been studied
by comparative analysis. Cyclic voltammograms at different scan rates show that the PCM capacitive
behavior in three electrolytes increases in the following order Li2SO4<Na2SO4<K2SO4. This
improvement could be a result of increasing the movement speed of hydrated ions in the volume
of electrolyte and in the internal pores of PCM in the order Li+<Na+<K+
. The obtained results give
valuable information for the study of new hybrid supercapacitors.
},
keywords = { activated carbon material, double electric layer, electrolyte, specific capacity, internal
resistance, electrochemical capacitor.},
tppubtype = {article},
tpstatus = {published},
}