Effect of Iron Oxide on Ionic Conductivity of Polyindole Based Composite Polymer Electrolytes G. RAJASUDHA 1,a , V. NARAYANAN 2,b and A. STEPHEN 1,c* 1 Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025, India 2 Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025, India. a rajasudhag@rediffmail.com, b vnnara@yahoo.co.in, c stephen_arum@hotmail.com Keywords: Composite materials, Polymer nanocomposite, Ionic Conductivity, dielectric properties Abstract. Composite polymer electrolytes (CPE) have recently received a great attention due to their potential application in solid state batteries. A novel polyindole based Fe 2 O 3 dispersed CPE containing lithium perchlorate has been prepared by sol-gel method. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte were examined by XRD, scanning electron microscopy, and impedance spectroscopy, respectively. The XRD data reveals that the intensity of the Fe 2 O 3 has decreased when the concentration of the polymer is increased in the composite. This composite polymer electrolyte showed a linear relationship between the ionic conductivity and the reciprocal of the temperature, indicative of the system decoupled from the segmental motion of the polymer. Thus Polyindole-Iron oxide composite polymer electrolyte is a potential candidate for lithium ion electrolyte batteries. The complex impedance data for this has been analyzed in different formalisms such as permittivity () and electric modulus (M). The value of ' for CPE decreases with frequency, which is a normal dielectric behavior in polymer nanocomposite. Introduction Composite Polymer Electrolytes (CPEs) are formed by dissolving a salt in a macromolecule, typically polymer such as poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) have received much attention over the last three decades for practical applications such as batteries, fuel cells, supercapacitors, hybrid power sources, display devices, sensors etc [1-3]. As it is well known, CPE have several advantages over the liquid counterpart such as desirable shape mouldability, free from leakage, mechanical strength and flexibility of design, thereby permitting miniaturization. Unfortunately, CPEs have the inherent problem of low ionic conductivity at ambient temperature that acts as a barrier to their utility when compared with the existing conventional liquid/hybrid electrolytes. To overcome these problems, the realization of single ion conduction is a fascinating alternative. Hence, it becomes important to understand the ion transport mechanism along with polymer segmental relaxation processes in polymer electrolyte. Therefore, the study of dielectric relaxation phenomena is a powerful tool for (i) understanding of the ion transport behavior and (ii) obtaining the information of ionic and molecular interaction in solid polymer electrolytes [4, 5]. The ion transport property depends on many factors like degree of salt dissociation and its concentration, dielectric constant of host polymer, degree of ion aggregation, and mobility of polymer chains [1]. Further, the ion association in a heterogeneous system is directly related to the presence of dipoles due to solvent ion pairs. So the dielectric properties of ionically conducting polymer electrolyte provide valuable information even though these materials have high ionic conductivity [6-8]. The dielectric relaxation and frequency dependent conductivity are both sensitive to the motion of charged species and dipoles of polymers. In view of the above, the aims to report dielectric and modulus spectra an ionically conducting composite polymer electrolyte system: polyindole-Fe 2 O 3 /LiClO 4 . In the present work, LiClO 4 complexed with the polyindole – iron oxide nanocomposite and composite polymer electrolyte was prepared and characterized by IR, XRD, SEM. The conductivity of these systems is studied by impedance spectroscopy. The effect of polymer concentration on frequency dependent Advanced Materials Research Vol. 584 (2012) pp 536-540 Online available since 2012/Oct/22 at www.scientific.net © (2012) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.584.536 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 14.139.186.162-22/11/12,12:13:06)