Nanocomposites and nanomaterials 

Relaxation of complex impedance 
in nano- and microcrystalline Li2O-xGeO2
Koptiev M.M., Plyaka S.M., Trubitsyn M.P., Volnianskii M.D., 
Krivchenko A.Yu. and Bieitsun M.D. 
Solid state physics and optoelectronics dept, Oles Honchar Dnipro National University, prosp. Gagarina 72, Dnipro, 49010, Ukraine.
E-mail: trubitsyn_m@ua.fm
Creation of electrically stable inorganic solid electrolytes is one of the promising ways to extend the operation time of autonomic power supplies. Increase of ionic conductivity by controlling chemical composition, atomic, nano- and micrometer sized structures is an actual problem of modern material sciences and the subject of intensive investigations. Family of lithium- germanium oxides Li2O-xGeO2 includes about ten stable compounds some of which are considered as the perspective matrixes for creation of new superionic conductors. Earlier in [1] it was shown that electrical conductivity of lithium heptagermante Li2O-7GeO2 single crystals was determined by Li interstitials moving through the structural channels. Later it was demonstrated that preparation of nanometer scaled partially crystallized states of Li2O-7GeO2 made it possible to increase ionic conductivity in three-four orders in comparison with single crystal [2].
It is known that studying the spectra of complex impedance can give valuable information on charge transfer processes in spatially inhomogeneous and multiphase systems. In the abstract we present the results of impedance spectra measurements in Li2O-xGeO2 (x=7, 11.5, 18) heat treated in nano- and microcrystalline states. The measurements were performed in the ranges 101-105 Hz and 400-700 K. The spectra were analyzed on the basis of equivalent circuit approach. The experimental data were interpreted with accounting the features of nano- and microscopic structures as well morphology of the samples studied [2].

1.	Volnianskii M., Plyaka S., Trubitsyn M. & Yahia Obaidat. Frequency dispersion of conductivity and complex impedance in Li2Ge7O15 single crystal // Ferroelectrics. – 2014.- 462. – P. 74-79.
2.	Nesterov O.O., Trubitsyn M.P., Nedilko S.G., Volnianskii M.D., Plyaka S.M., Rybak Ya.O. Ionic conductivity in multiphase Li2O-7GeO2 compounds// Acta Physica Polonica A. – 2018. – 133, № 4.– P. 892-896.