Enhancing structural, thermal, and electrical properties of plasticized lithium-based PVdF-HFP polymer electrolytes for flexible energy storage applications

Lithium ion-conducting plasticized polymer electrolyte membranes were prepared using poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) as the host polymer, lithium triflate (LiTf) as the dopant salt, and ethylene carbonate (EC) as the plasticizer, with varying compositions accomplished using the solution casting technique. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) analyses validate the presence of substantial structural alterations and the formation of a complex in the plasticized polymer electrolytes. The electrochemical impedance spectroscopy (EIS) analysis demonstrates an increase in ionic conductivity by about two orders of magnitude after the addition of EC. Estimates of ionic transference numbers derived from the direct current (DC) polarization approach indicate that charge transport in plasticized polymer electrolytes is mostly ionic. We examined the discharge characteristics of our flexible electrochemical storage device (FESD) over 25 h. The mean discharge current is 1.4 mA with a 0.04 C rating.