Detailed Investigation into the Electrical Conductivity and Structural Properties of Poly(ethylene oxide)-succinonitrile-Li(CF3SO2)(2)N Solid Polymer Electrolytes

摘要

A solid polymer electrolyte (SPE) was prepared via a solution casting method from a blend of equal weight fractions of poly( ethylene oxide) (PEO) and succinonitrile, used as the polymer matrix, and a salt, Li( CF3SO2)(2)N (x = 0-0.3 in weight fraction). A plot of the electrical conductivity (sigma 25 degrees C) vs. x showed an upturned U-shape, with the highest value being similar to 3.9 x 10(-4) S/cm for x = 0.25 ( EO/Li+ = 9.8; the optimum conducting composition). The electrolytes with x ranging from 0.15 to 0.3 showed a linear trend in their log(sigma T-0.5) - (T-To)(-1) curves with low pseudo-activation energy values, suggesting the presence of highly conductive amorphous domains, as confirmed by X-ray diffractometry measurements, Fouriertransform infrared (FT-IR) spectroscopy, polarized optical microscopy, and differential scanning calorimetry studies. The change in PEO chain conformation with x is discussed in detail using FT-IR spectroscopy in the light of earlier results reported for PEO - Li(CF3SO2)(2)N SPEs.