A Detailed Investigation into the Electrical Conductivity and Structural Properties of [Poly(ethylene oxide)‐succinonitrile]‐Li( CF 3 SO 2 ) 2 N Solid Polymer Electrolytes

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( CF 3 SO 2 ) 2 N ( x = 0–0.3 in weight fraction). A plot of the electrical conductivity (σ 25°C ) vs. x showed an upturned U‐shape, with the highest value being ~3.9 × 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(σ T 0.5 ) − ( T − T o ) −1 curves with low pseudo‐activation energy values, suggesting the presence of highly conductive amorphous domains, as confirmed by X‐ray diffractometry measurements, Fourier‐transform 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( CF 3 SO 2 ) 2 N SPEs .