Effect of plasticizer on structure—property relationship in composite polymer electrolytes

• Published in: Journal of power sources 2005-01, Vol.139 (1), p.384-393
• Main Authors: Pradhan, Dillip K., Samantaray, B.K., Choudhary, R.N.P., Thakur, Awalendra K.
• Format: Article
• Language: English
• Subjects: Applied sciences; Crystallinity; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy storage/conversion devices; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Glass transition; Impedance; Ion transport; Plasticization
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2004.05.050

A new plasticized composite polymer electrolyte (PCPE) based on poly(ethylene oxide)–NaClO 4 dispersed with a ceramic filler (SnO 2) and plasticized with polyethylene glycol (PEG 200) is reported. The effect of plasticizer concentration on changes in structure/microstructure and their correlation with physical properties has been investigated and reported. A substantial enhancement in the electrical conductivity, by two orders of magnitude at room temperature, of the PCPE has been noticed when compared with that of composite polymer electrolyte (CPE) films without any plasticizer. This enhancement in electrical conductivity of the PCPE films agrees well with the changes in the local microstructure/structure on plasticizer addition. Grain boundary resistance ( R gb) and glass transition temperature ( T g) have been observed to decrease with increasing concentration of PEG 200. Plasticizer addition has resulted in the suppression of crystallinity as observed from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. The DSC results indicate enhancement in the volume fraction of the amorphous phase, which appears to be consistent with the broadening in the polymer host peaks observed in X-ray diffractograms. The improvement in electrical conductivity has been achieved without any sharp deterioration in the thermal, electrochemical or mechanical stability of the PCPE thin films. These observations have been interpreted in terms of the action of plasticizer as a diluent/co-solvent.