THE RELATIONSHIP BETWEEN STRUCTURE, ELECTRICAL AND DIELECTRIC PROPERTIES OF THE ION-CONDUCTING POLYMER COMPOSITES BASED ON THE EPOXY OLIGOMERS AND THE LITHIUM PERCHLORATE SALTS

Solid polymer electrolytes (SPE) have received a great attention to the decisive role as an ionic conductor in various electrochemical devices. Significant efforts have been devoted to the high ionic conductivity with better mechanical stability of SPE. The aim of this work is to investigate the relationship between structure, electrical and dielectric properties of the crosslinked ion-conducting polymers based on a mixture of oligomers with similar functional epoxy groups. The effect of lithium perchlorate salt content on structure and properties of the synthesized polymer systems based on aliphatic epoxy oligomer – diglycidylether of ethylene glycol DEG-1 and epoxy-diane resin ED-20, which were cured by polyethylene polyamine, has been studied by means of the Differential Scanning Calorimetry, the Wide Angle X-ray Diffraction and the Broadband Dielectric Spectroscopy. It was found that the glass transition temperature of the synthesized systems increases with increasing amount of the LiClO4 that is connected with formation of coordination complexes between lithium cations and atoms of macromolecular chains. Presence of one single diffraction maximum of the diffuse type, an angular value of which is approximately 19.6, on the wide angle X-ray diffractograms indicates that systems are amorphous and they are characterized by the short-range ordering. The real parts of permittivity and complex electrical conductivity depend on the content of lithium perchlorate salt and temperature of measurements. The maximum level of ionic conductivity and permittivity at elevated temperatures was revealed for the systems with a concentration 30 phr. of the lithium perchlorate salt. 

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