Arrhenius and non-Arrhenius conductivities in intercalated polymer electrolytes

Jeevanandam, P and Vasudevan, S (1998) Arrhenius and non-Arrhenius conductivities in intercalated polymer electrolytes. In: Journal of Chemical Physics, 109 (18). pp. 8109-8117.

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Abstract

Intercalated polymer electrolytes (IPEs), Cd(0.75)PS(3)A(0.5)(PEO) [A = Li, Na, K, Cs], formed by the insertion of alkali metal ions solvated by polyethylene oxide (PEO) into the interlamellar space of the layered insulating cadmium thio-phosphate form an interesting class of materials. Their ambient temperature dc conductivities are comparable to that of the corresponding solid polymer electrolytes (SPEs) formed by dissolving alkali-metal salts in PEG. The conductivity of the intercalated materials, irrespective of the cation, exhibits a change in conduction mechanism with temperature. At low temperatures (T < 225 K) the dc conductivity values are small and exhibit an Arrhenius temperature dependence. Above 225 K the dc conductivity rises sharply and in this temperature regime its temperature variation depends on the alkali-cation. The dc conductivity of the Li and Na containing IPEs follow the non-Arrhenius Vogel-Tamann-Fulcher (VTF) relation, sigma(dc) = sigma(0)T(-0.5) exp(-B/(T - T-0)), while the K and Cs IPEs follow an Arrhenius dependence. The origin of the Arrhenius and non-Arrhenius conductivity of the IPEs, Cd(0.75)PS(3)A(0.5)(PEO) [A = Li, Na, K, Cs], have been investigated by analyzing the frequency-dependent conductivity in the dielectric and electrical modulus representations. We show that the difference in behavior is related to differences in the coupling of ionic motion and polymer segmental modes. In the Li and Na containing IPEs the motions are coupled and the conductivity exhibits a VTF temperature dependence. In the K and Ca compounds these motions are decoupled, consequently, although the mean relaxation time associated with segmental motion of the intercalated PEO exhibits a VTF dependence, ionic conductivity has an Arrhenius temperature dependence. (C) 1998 American Institute of Physics. [S0021-9606(98)52241-6]

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	25 Feb 2009 05:41
Last Modified:	19 Sep 2010 04:59
URI:	http://eprints.iisc.ac.in/id/eprint/18061

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