Solid polymer electrolytes comprising of various weight ratios of poly(ethyl

methacrylate) (PEMA) and lithium perchlorate (LiCl04) salt were prepared via solution casting technique using N,N-Dimethylformamide (DMF) as the solvent. The conductivity values of the electrolytes were determined utilizing Solatron 1260. The highest conductivity obtained is in the

order of 10-6 S ern -I. Structural properties of the electrolytes were investigated by X-ray diffraction

and the results show that the highest conducting film is the most amorphous

Amir, S.

Mohamed, N.S.

Yahaya Subban, R.H.

UM Digital Repository

Advanced Materials Research Vats. 93-94 (2010) pp 38/-384© (2010) Trans Tech Publications, Switzerlanddoi: 10.4028lwww.scientific.netIAMR.93-94.381The Investigation on Ionic Conduction of PEMA Based Solid PolymerElectrolytesShahrul Amir ': a, Nor Sabirin Mohamed" band Ri Hanum Yahaya Subbarr': c'Department of Engineering, Center for Foundation StudiesInternational Islamic University of Malaysia, 46350 Petaling Jaya, Selangor, Malaysia2Center for Foundation Studies in Science, University of Malaya, 50603 Kuala Lumpur, Malaysia3Faculty of Applied SCiences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysiaajcv90210@yahoo.com, bnsabirin@um.edu.my, crihanum43@salam.uitm.edu.myKeywords: polymer electrolytes. conductivity, XRO, scherrer length, dielectric constantAbstract. Solid polymer electrolytes comprising of various weight ratios of poly(ethylmethacrylate) (PEMA) and lithium perchlorate (LiCl04) salt were prepared via solution castingtechnique using N,N-Dimethylformamide (DMF) as the solvent. The conductivity values of theelectrolytes were determined utilizing Solatron 1260. The highest conductivity obtained is in theorder of 10-6S ern -I. Structural properties of the electrolytes were investigated by X-ray diffractionand the results show that the highest conducting film is the most amorphous.IntroductionPolymer is a material constructed of a large number of molecules that is formed from the repetitionof small and simple chemical units called monomer bonded by covalent bonds. Most polymers haveno ability to conduct electricity. Besides its poor electrical conductivity property, for the last fivedecades, ion conducting polymers has been synthesized via dissolving inorganic salt into its matrix.Polymer electrolytes possess various advantages such as solvent free condition, structurally stable,easy for any process and mobileable [1]. Various kinds of polymers have been chosen as host suchas PEO [2], PPO [3], PVA [4,5], PVC [6], PVDF [7] and PMMA [8]. In this work, the potential ofPEMA as a polymer host is investigated. LiCI04 is added as the doping salt. PEMA was chosen ashost as it exists in amorphous form [9]. By incorporating LiCl04 in to PEMA, it was hoped that themedia for ion mobilities will be enhanced.ExperimentalVarious weight percentages, wt% of LiCl04 was dissolved into commercially available PEMA (M;= 2) 5,000) employing DMF as solvent. The films were cast using the solution casting method. Thecast films were subjected to EIS (Solatron 1260) and XRD analysis (LabX XRD 6000) forimpedance and structural studies respectively.Results and DiscussionFig. 1 depicts the X-Ray diffractograms of PEMA-LiCI04 films at various concentrations. For purePEMA, the XRD pattern obtained in this work is similar to that obtained by Rajendran et.al [10]that is a small peak appeared at 28"" 29.5°. PEMA-LiCl04 diffractograms show a few peaks due tothe presence of LiCI04 and is prominent for the film with 30 wt% LiCI04• Such observation is mostpossibly due to the uncomplexed salt or ion aggregation of the salt. For 30 wt% LiCI04 the degreeof uncomplexed salt or ion aggregation is the highest.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 thepublisher: Trans Tech Publications Ltd, SWitzerland, www.ttp.net. (ID: 202.185.78.6-21/12109,06:45:18)(O""UII"'ff""~''''(Qllf .•Ht382 Functionalized and Sensing Materials(g)(f)--(e)-~..(d)(e)(b)(a):ae '"----~--~~.~~------- ---~-.--------~ -~............20 22 " " 30 32 3629Fig. 1: X-ray diffractograms of PEMA with (a) 0, (b) 5, (c) 10, (d) 15, (e) 20, (f) 25 and (g) 30 wt%LiCI04•The Scherrer length, L, for every sample was determined using the equationL = o.nA28 . (28max)L.1 halfpeak SIn --2(I)owhere A, = 1.5418 A and 1:l2fJ is the width at half maximum. In this work, Scherrer length wascalculated using the peak at 29.5° and it shows that the sample with 20 wt % LiCl04 has thesmallest value as observed in Fig. 2. According to Hashmi et.al [11], the smaller the value of L, themore amorphous the sample is. Hence the most amorphous film has ratio of 80 wt % PEMA:20wt% LiCl04..,J 35~ E' 2.8Q),g~ CI) 2.6Q) 0)~ ~ 2.4.c:~oCI) 2.23.220% 5% 10% 15% 20% 25% 30% 35%Percentage of SaltFig. 2: Scherrer length for PEMA-LiCI04 filmsGraph of e, - log OJ depicted in Fig. 3 for all films. The dielectric constant is observed to risesharply at low frequencies. According to Mohamed and co-worker [12], this indicates that electrodepolarization and space charge effects had occurred. r'Ht\u!!(~"""elllAdvanced Materials Research Vols. 93-94 383-1200I 12000.. 10000 ....8000 ....I .. (e) 11000 ~ 6000\.40002000..02.5 4.5 6.5800log OJ..r-• (e)600 .. .. (d)oj • (b)• .. ~•400 ..•• .. •• .. •• •200 ...... .... ..~ .. .'~....._ ....... -................02.5 3.5 4.5 5.5 6.5 7.5Log OJFig. 3: e, -log (JJ graph ofPEMA with (a) 10, (b) 15, (c) 20, (d) 25, (e) 30 wt% LiCI04filmsSince e; is a reflection of the number of charge carriers present, hence it can be inferred that thesample with 20 wt % LiCI04 has the highest number of charge carriers and is expected therefore tohave the highest conductivity. This is supported by the graph shown in Fig. 4 which shows thevariation of conductivity with salt concentration at room temperature. From Fig. 4, the highestconductivity obtained is 2.34 x 10-6 S ern" for the sample with 20 wt % LiCI04. This is comparableto the value of conductivity obtained for other dry polymer electrolytes reported in the literature[13,14,15]1.00E-05~ '.00E~61~ 1.00E-07b~ 1.00E-08>~-6 1.00E-09c:oo 1.00E-101.00E-110% 5% 10% 15% 20%Percentage of salt25% 30% 35%Fig. 4: Conductivity variation with salt concentration of PEMA-LICI04 filmsFig. 4 also shows that the conductivity decreases for films with more than 20 wt % LiCI04. This isattributed to the decrease in the fraction of amorphous region and decrease in the number of chargecarriers as indicated in Fig. 2 and Fig. 3 respectively.{o,,\ulllJ!r>','."1384 Functionalized and Sensing MaterialsConclusionThe highest conductivity achieved in this work is 2.34 x 10-6 Scm" for the ratio of PEMA addedwith 20 wt % LiCI04. There are still opportunities to increase the conductivity perhapsincorporating the existing samples with plasticizers or nanofillers. The results of this study indicatethat PEMA has good potential to act as polymer host for electrolyte systems.AcknowledgementThe authors are very thankful to Dr. Raihan Othman for his contribution in making the XRDanalysis possible for this research project.References[I] S. Ramesh, T. Winie and A.K. Arof: European Polymer Journal Vol 43 (2007), p. 1963[2] E.A. Reitman, M.L.R. Kaplan and J. Cava: Solid State Ionics Vol 25 (1987), p. 37[3] C. Roux, W. Gorecki, J. Y. Sanchez and E. Belorizky: Electrochem. Acta Vol 43 (1998), p.1575[4] N. Srivastava, S. Chandra: Proceedings of 5th Asian Conference on Solid State Ionics 411,Kandy Sri Lanka (1996)[5] P.K. Shukla and S.L. Agrawal, Proceedings of the 6th Asian Conference on Solid State Ionics,New Delhi India (1998)[6] R.H.Y. Subban and A.K. Arof: Journal of New Materials for Electrochemical Systems Vol 6(2003), p.l 97[7] N.S. Mohamed and A.K. Arof: Journal of Power Sources, Vol 132 (2004), p.229[8] A.M. Stephan, R. Thirunakaran, N.G. Reganathan, V. Sundaram, S. Pitchumani, N. Muniyandi,R. Gangadharan and P. Ramamoorthy: Journal of Power Sources Vol 81-82 (1999), p. 752[9] on http://www.polymerprocessing.com/polymersIPEMA.html[10] S. Rajendran, M. Ramesh Prabhu and M. Usha Rani: Journal of Power Sources Vol 180(2008), p.880[11] S.A. Hashmi, Awalendra K. Thakur and H.M. Upadhyaya: European Polymer Journal Vol 34(1998), p.1277[12] N.S. Mohamed and A.K.Arof: Journal of Power Sources Vol 132 (2004), p.229[13] K. Ito, Y. Tominaga, H. Ohno: Electrochimica Acta, Vol 42 (1997), p. 1561[14] G. Chiodelli, P. Ferloni, A. Magistris, M. Sanesi: Solid State lonics, Vol 28-30, Part 2 (1988),p.l009[15] A.M.M. Ali, N.S. Mohamed, M.Z. Zakaria, A.K. Arof: Journal of Power Sources, Vol 66,(1997), p.J 69

The investigation on ionic conduction of PEMA based solid polymer electrolytes

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The investigation on ionic conduction of PEMA based solid polymer electrolytes

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