Na-Ion Conducting Gel Polymer Electrolytes Based on Polyvinylidenefluoride-Co-Hexafluoropropylene with Sodium Trifluoromethane-Sulfonate

Polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) gel polymer electrolytes (GPEs) consisting of sodium trifluoromethane-sulfonate or sodium triflate were prepared for sodium ion battery application. The GPEs at different weight percent ratios of salt content were prepared by solution casting technique. The effects of changes in salt concentration on the structural and electrical properties were investigated. FTIR studies confirm that conductivity enhancement is due to the increase in free ions and decrease in ion aggregates. Impedance studies indicate that the highest ionic conductivity of 2.50 x 10(-3) S / cm was observed with the addition of 25 wt. % of sodium salt concentration in GPEs system obtained at ambient temperature. The transport number of sodium ions in the GPEs was evaluated using the combination of AC impedance spectroscopy and DC polarization techniques.