Conducting Solid Polymer Blend Electrolytes Based on Three Synthetic Polymers for Sodium Battery Applications

Polymer blend electrolytes are prepared by blending three polymers—Polyvinyl alcohol:Polyvinyl pyrrolydone:Polyethylene glycol ( PVA ∶ PVP ∶ PEG ) with the addition of inorganic salt sodium nitrate ( NaNO 3 )—by using a solution casting technique. X-ray diffraction (XRD) is used to confirm that the produced polymer electrolytes are amorphous. Fourier transform infrared spectroscopy (FTIR) analysis is used to determine the complexation and chemical bonding between the electrolytes’ salt and polymers. The morphology of the polymer electrolytes is verified using scanning electron microscopy (SEM). From impedance studies, the ionic conductivity and activation energy of the electrolytes are evaluated. The maximum ionic conductivity and minimum relaxation time is observed for the PVA / PVP / PEG / NaNO 3 ( 40 ∶ 40 ∶ 20 ∶ 10 mw % ) system. The higher conducting polymer electrolyte has low activation energy that enhances ionic conductivity through the polymer matrix. Temperature-dependent Arrhenius behavior is observed for all prepared polymer electrolytes. It is proved that ionic conductivity of the films increases with salt concentration up to a limit. It is discovered that the optimized higher conducting electrolyte has a higher dielectric constant and dielectric loss. The low bandgap of the higher conducting polymer electrolyte has been demonstrated. Transference number studies demonstrated that the polymer electrolytes are effective ionic conductors. A sodium battery with good rechargeability has been fabricated using the higher conductivity polymer electrolyte.