Structural and ion transport properties of lithium triflate/poly(vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes: Effect of lithium salt concentration

Polymer electrolytes consisting of poly(vinylidene fluoride-co-hexafluoropropylene) in combination with lithium triflate (LiCF3SO3) salt of varying concentration have been prepared using the conventional solution casting technique in the argon atmosphere. Structural electrical characterizations of the synthesized electrolytes have been performed using various imaging and spectroscopic techniques. The DC conductivities determined by complex impedance plots reveal gradual increasewith increase in salt concentration up to a particular limit and decrease subsequently. The maximum DC conductivity obtained at 300 K is 1.64 x 10(-4) Scm(-1) for the electrolyte with a polymer to salt weight ratio of 1: 1.8. The temperature-dependent conductivity followed a mixed Arrhenius and VogelTamman- Fulcher type behaviour for the polymer electrolytes. From the Summerfield master curve plot, the conductivity of the solid polymer electrolytes is found to depend not only on ion dynamics but also on the segmental mobility of the polymer chains.