CHARACTERIZATION OF POLYACRYLONITRILE BASED CONDUCTING POLYMER ELECTROLYTE FILMS

Abstract

The conducting polymer electrolyte films composed of polyacrylonitrile (PAN) as the host polymer, LiCF₃SO₃ and NaCF₃SO₃ as inorganic salts were prepared by the solution cast technique. The pure PAN film was prepared as a reference. XRD studies show that the complexation has occurred in the PAN containing salt films and complexes formed are amorphous. These results correspond with surface morphology images obtained from SEM analysis. DSC analysis show that the glass transition temperature, T_g of PAN film has decreased on addition of salts. The ionic conductivity for the films is characterized using impedance spectroscopy. The room temperature conductivity for the PAN + 26wt.% LiCF3SO3 film and the PAN + 24wt.% NaCF₃SO₃ film is 3.04 x 10 4 Scm^-1 and 7.13 x 10^-4 Scm^-1, respectively. The PAN containing NaCF₃SO₃ film has a higher ionic conductivity compared to the PAN containing LiCF₃SO₃ film. These results can be explained based on the Lewis acidity of the alkali ions, i.e., the interaction between Li⁺-ion and the nitrogen atom of PAN is stronger than that of Na⁺ ion. The temperature dependence of the conductivity follows Arrhenius equation in the temperature range of 303 K to 353 K.