NMR and Conductivity Study of Starch BasedPolymer Gel Electrolytes

Abstract

Nuclear Magnetic Resonance spectroscopy (NMR) and complex impedance spectroscopy have been used to study the polymer gel electrolytes formed by amylopectin rich starch, plasticized with glycerol and containing lithium perchlorate. The use of plasticizer enhances the conductivity, which reaches ∼10−4 S/cm at room temperature. The 7Li NMR decoupling experiments performed at 183 K show that 80% of the sub-T g linewidth is attributable to the heteronuclear Li-H interaction, suggesting a weaker Li – polymer interaction in the plasticized electrolyte when compared with the unplasticized ones. The Li-7 NMR results exhibit the qualitative features associated with the lithium mobility in the polymer gel electrolyte, namely the presence of a well defined Li-7 spin-lattice relaxation maxima at 340 K.