Title:	The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM] [TFSI] solid polymer electrolyte
Authors:	Sedlák, Petr Gajdoš, Adam Macků, Robert Majzner, Jiří Holcman, Vladimír Sedláková, Vlasta Kuberský, Petr
Citation:	SEDLÁK, P. GAJDOŠ, A. MACKŮ, R. MAJZNER, J. HOLCMAN, V. SEDLÁKOVÁ, V. KUBERSKÝ, P.The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM] [TFSI] solid polymer electrolyte. Scientific Reports, 2020, roč. 10, č. 1, s. „21140-1" - „21140-12". ISSN 2045-2322.
Issue Date:	2020
Publisher:	Nature Research
Document type:	článek article
URI:	2-s2.0-85097095469 http://hdl.handle.net/11025/42958
ISSN:	2045-2322
Keywords in different language:	solid polymer electrolyte;current fluctuations;Poly(vinylidene fluoride);imidazolium ionic liquid;solvent evaporation temperature;conductivity;Vogel-Fulcher-Tammann dependence;interdigital electrode
Abstract in different language:	The experimental study deals with the investigation of the effect of diverse crystallinity of imidazolium ionic-liquid-based SPE on conductivity and current fluctuations. The experimental study was carried out on samples consisting of [EMIM][TFSI] as ionic liquid, PVDF as a polymer matrix and NMP as a solvent. After the deposition, the particular sample was kept at an appropriate temperature for a specific time in order to achieve different crystalline forms of the polymer in the solvent, since the solvent evaporation rate controls crystallization. The ac/dc conductivities of SPEs were investigated across a range of temperatures using broadband dielectric spectroscopy in terms of electrical conductivity. In SPE samples of the higher solvent evaporation rate, the real parts of conductivity spectra exhibit a sharper transition during sample cooling and an increase of overall conductivity, which is implied by a growing fraction of the amorphous phase in the polymer matrix in which the ionic liquid is immobilized. The conductivity master curves illustrate that the changing of SPEs morphology is reflected in the low frequency regions governed by the electrode polarization effect. The dc conductivity of SPEs exhibits Vogel–Fulcher–Tammann temperature dependence and increases with the intensity of thermal treatment. Spectral densities of current fluctuations showed that flicker noise, thermal noise and shot noise seems to be major noise sources in all samples. The increase of electrolyte conductivity causes a decrease in bulk resistance and partially a decrease in charge transfer resistance, while also resulting in an increase in shot noise. However, the change of electrode material results in a more significant change of spectral density of current fluctuations than the modification of the preparation condition of the solid polymer electrolyte. Thus, the contact noise is considered to contribute to overall current fluctuations across the samples.
Rights:	© Nature Research
Appears in Collections:	Články / Articles (KET) OBD

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