Electrical conductivity relaxation in PVOH-LiClO4-Al2O3
Artikel i vetenskaplig tidskrift, 2007

We report on electrical conductivity relaxation measurements of solid polymer electrolytes (SPE) based on poly(vinyl alcohol) (PVOH) and LiClO4 in which nanoporous Al2O3 particles with average pore diameter of 58 angstrom were dispersed. A power law frequency dependence of the real part of the electrical conductivity is observed as a function of temperature and composition. This behaviour is typical of systems in which correlated ionic motions in the SPE bulk material are responsible for ionic conductivity. This variation is well fitted to a Jonscher expression sigma'(omega)= sigma(0)[l +(omega/omega(0))(P)] where sigma(0) is the dc conductivity, omega(0) the characteristic angular frequency relaxation and p is the fractional exponent between 0 and 1. For a prototype membrane with composition 0.9PVOH - 0.1LiClO(4) +7wt.%Al2O3, it was found that the temperature dependence of sigma(0) and omega(0), may be described by the VTF relationship, phi = phi(0) exp[-BI(T - T-0)], with approximately the same constant B and reference temperature T-0, indicating that ion mobility is coupled to the motions of the polymer chains. Moreover, p decreased with increasing temperature, from 0.68 at T=319K, to 0.4 at T=437 K, indicating weaker correlation effects among mobile ions when the temperature is increased. (c) 2007 Elsevier Ltd. All rights reserved.

POLY(VINYL ALCOHOL)

GLASSES

electrical relaxation

poly(vinyl alcohol)

MEMBRANES

SPECTROSCOPY

ION-TRANSPORT

composite

ionic

POLYMER ELECTROLYTES

conductivity

Författare

W. A. Castro

Universidad del Valle

V. H. Zapata

Universidad del Valle

R. A. Vargas

Universidad del Valle

Bengt-Erik Mellander

Chalmers, Teknisk fysik, Fasta tillståndets fysik

Electrochimica Acta

0013-4686 (ISSN)

Vol. 53 4 1422-1426

Ämneskategorier

Annan teknik

DOI

10.1016/j.electacta.2007.05.066