Impedance spectroscopy of carbon nanotube/solid polymer electrolyte composites

New composite polymer electrolytes (CPE) have been prepared by a solution-casting technique, using polyethylene oxide, lithium hexafluorate (LiPF6) as the doping salt, ethylene carbonate (EC) as the plasticizer and amorphous carbon nanotubes (ααCNTs) as the filler. The crystallinity and ionic conductivity of the CPE are examined. Differential scanning calorimetry shows a decrease in melting temperature and crystallinity upon the addition of LiPF6, EC and ααCNTs to the polymer electrolyte system. The addition of salt increases the conductivity up to 10−5 S cm−1. The incorporation of EC and ααCNTs into the salted polymer shows a significant conductivity increase of 10−4 and 10−3 S cm−1. The complexation process is examined using Fourier transform infrared spectroscopy. The Vogel–Tamman–Fulcher (VTF) plots suggest that the temperature dependence of conductivity is a thermally activated process.

► New composite polymer electrolytes have been prepared by a solution-casting technique. ► The amorphous carbon nanotubes (ααCNTs) were added into plasticized polymer electrolytes. ►ααCNTs effect in increasing of conductivity in polymer electrolyte. ► It is due to highly flexible ααCNTs into PEO networks. ► Improved the interaction and cross-linking between ααCNTs and PEO.