To the top

Page Manager: Webmaster
Last update: 9/11/2012 3:13 PM

Tell a friend about this page
Print version

Dielectric relaxation, io… - University of Gothenburg, Sweden Till startsida
Sitemap
To content Read more about how we use cookies on gu.se

Dielectric relaxation, ionic conductivity and thermal studies of the gel polymer electrolyte system PAN/EC/PC/LiTFSI

Journal article
Authors P. A R D Jayathilaka
M. A K L Dissanayake
Ingvar Albinsson
B. E. Mellander
Published in Solid State Ionics
Volume 156
Pages 179-195
ISSN 01672738
Publication year 2003
Published at Department of Physics (GU)
Pages 179-195
Language en
Keywords Dielectric relaxation, Gel polymer electrolyte, Ionic conductivity, PAN/EC/PC/LiTFSI, Thermal studies
Subject categories Condensed Matter Physics

Abstract

Dielectric relaxation, ionic conductivity and thermal properties have been measured for the gel polymer electrolyte system poly(acrylonitrile)/ethylene carbonate/propylene carbonate/lithium bis(trifluoromethanesulfone)imide (PAN/EC/PC/LiTFSI) and for its components in the frequency range from 1 MHz to 1.8 GHz and over a temperature range from -20 to 50 °C. DSC results suggest that EC/PC exists in two different environments within the gel network; as regions in which the EC/PC molecules subjected to pairing interactions by the CN group in PAN and also as regions consisting of "free" EC/PC molecules. Addition of PAN to the EC/PC/LiTFSI liquid electrolyte has increased the ionic conductivity. Out of the various PAN/LiTFSI composition ratios studied for the gel polymer electrolyte, the 6:1 composition ratio by weight gives the highest ionic conductivity. The room temperature (23 °C) conductivity of the gel electrolyte with this composition, PAN(15.4%)/EC(41.0%)/PC(41.0%)/LiTFSI(2.6%) (by weight) is 2.5 × 10-3 S cm-1. DSC results show that this composition has the most amorphous nature, above -105 °C. The ε″ spectra of gel electrolytes with various compositions show the presence of a high-frequency peak in the 0.5-GHz region attributed to the α relaxation process and a peak/shoulder in the 10-MHz region attributed to the ion-pair relaxation. Li+ ion transport probably takes place in the vicinity of the PAN chains and the ion-pair relaxation frequency appears to reflect the dynamic environment in which the cations migrate. However, the coupling between the conductivity and the α relaxations, attributed to EC/PC molecules, appears to be weak. A model has been presented according to which the Li+ ions in the gel electrolyte appears to be solvated by both PAN (through CN) and EC/PC. © 2003 Elsevier Science B.V. All rights reserved.

Page Manager: Webmaster|Last update: 9/11/2012
Share:

The University of Gothenburg uses cookies to provide you with the best possible user experience. By continuing on this website, you approve of our use of cookies.  What are cookies?