FT-IR and DSC studies of poly(vinylidene chloride-co-acrylonitrile) complexed with LiBF4

Poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN) based solvent free electrolytes were prepared for different compositions of PVdC-co-AN and LiBF4 using solution casting technique. The ionic conductivity, thermal behavior, complexation and structure of polymer electrolytes have been investigated as a function of LiBF4 content at different weight ratios. DSC studies revealed that the glass transition temperature Tg decreases with the increase of salt concentration up to an optimum level. The change in the glass transition temperature (Tg) with respect to the LiBF4 concentration is reflected in the bulk resistance of the electrolytes and the sample containing 6 wt.% of LiBF4 exhibited minimum bulk resistance compared to other samples. FT-IR studies confirm the interaction of polymer and salt which is mainly between Li-cation and nitrogen atom of CN group. The crystalline phase of polymer host is completely changed on the addition of Li salt.

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► Poly(vinylidene chloride-co-acrylonitrile) based polymer free electrolytes were prepared using solution casting technique.
► The structural and functional group studies were carried out using XRD and FT-IR.
► The optimal salt concentration was found to be 6 wt.%.