Conductivity, thermal and infrared studies on plasticized polymer electrolytes with carbon nanotubes as filler

摘要

New composite polymer electrolytes (CPE) are prepared using solution-casting technique. The CPE are based on polyethylene oxide (PEO) and employ lithium hexafluorate (LiPF6) as the doping salt, ethylene carbonate (EC) as the plasticizer and amorphous carbon nanotubes (αCNTs) as the filler. The crystallinity and ionic conductivity of the CPE are examined in this work. The conductivity increases from 10~(-10) to 10 ~(-5) S cm~(-1) upon the addition of salt. The incorporation of EC and αCNTs into the salted polymer enhances the conductivity significantly to 10~(-4) and 10~(-3) S cm~(-1). The Vogel-Tamman-Fulcher (VTF) plots suggest that the temperature dependence of conductivity is a thermally activated process. Differential Scanning Calorimetry (DSC) studies show that the melting transition temperature and crystallinity decrease upon the addition of salt, EC and αCNTs into the polymer electrolyte system. The complexation, nature and concentration of the various ionic species are examined using Fourier Transform Infrared Spectroscopy (FTIR). Scanning electron microscopy (SEM) images show the changes in morphologies of the composite polymer electrolytes. The application of CPE especially in batteries and the advantages of this composite are highly conductive and stable at elevated temperature.