The preparation and characterization of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)-based Na+ conducting gel polymer electrolytes (GPEs), incorporating sodium salts with three different anions, BF 4 − , ClO 4 − , and CF3SO 3 − salts dissolved in the ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) are reported. Among the studied systems, the GPE containing the same anion in both the salt and the ionic liquid, i.e., NaBF₄/EMIMBF₄, exhibits the highest ionic conductivity of approximately 4.2 mS·cm−1 at room temperature. The ion dynamics of the GPEs is investigated using dielectric (ε∗) and modulus (M∗) analyses over a wide frequency range through electrochemical impedance spectroscopy. The cyclic voltammetry (CV) studies reveal the Na+ conducting nature of the optimized GPE by showing peaks associated with depositing and removal of Na+ at Na–Hg electrodes. The optimized composition shows excellent electrochemical stability window of 5 V. The interaction of BF 4 − , ClO 4 − and CF3SO 3 − anions with PVdF-HFP and EMIMBF4 has been confirmed using Fourier transformed infra-red (FTIR) spectroscopy. The high-conducting electrolytes of this report can be utilized for future applications in electrochemical devices.
