More studies on the PVOH-LiH2PO4 polymer system
Artikel i vetenskaplig tidskrift, 2007
Polymer electrolytes based on poly(vinyl alcohol) (PVOH) and lithium dihydrogen-phosphate (LiH2PO4) with molar ratio of x = 0.07, 0.10 and 0. 14 were prepared in order to investigate the mechanism of ionic motion. Admittance spectroscopy measurements were used to study electrical conductivity relaxation on both anhydrous and hydrated samples in the 5 Hz to 13 MHz frequency range and temperatures ranging from 25 to 150 degrees C. The conductance, G, shows dispersion above a crossover frequency, f(p). This behavior is typical of systems in which correlated ionic motions in the bulk material are responsible for ionic conductivity. For hydrated samples, results reveal that the temperature dependence of the dc-conductivity, sigma(0) and the characteristic frequency,f(p), shows Arrhenius-type behavior with the same energy, E-sigma. However, for anhydrous conductivity, a Vogel-Tamman-Fulcher (VTF) behavior is shown for both sigma(0)(T) and f(p)(7), with the same pseudo activation energy, B and B-sigma, respectively, thus indicating that they are correlated with chain mobility. (c) 2007 Published by Elsevier Ltd.