Ionic conductivity in PEO-LiCF3SO3-EC/DMC-PAN hybrid films

Hybrid solid electrolyte films consisting of poly(ethylene oxide) (PEO), LiCF3SO3, a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) and poly (acrylonitrile) (PAN) were examined in order to obtain the best compromise between high conductivity, homogeneity and dimensional stability. Measurements of electrical conductivity and differential scanning calorimetry (DSC) have been carried out. The higher the content of solvent (EC/DMC), the higher the conductivity. The highest conductivity of 1.6 x 10(-3) S/cm at 30 degrees C is found for a film of 28PEO-7LiCF(3)SO(3)-55EC/DMC-10PAN. The materials having higher EC/DMC content are more likely to be a gel-electrolyte than a plasticized PEO-salt electrolyte. The Li+ ions in these films seem to migrate primarily through the solvent domains as in the gel-electrolytes. The PEG-PAN hybrid film exhibits high ionic conductivity comparable to that of PAN-based gel electrolytes, good mechanical strength and, therefore, is a promising candidate for solid electrolytes of lithium polymer batteries.