Structural, morphological, electrical and electrochemical study on plasticized PVdF-HFP/PEMA blended polymer electrolyte for lithium polymer battery application

Abstract

The compositional effect of blending plasticized poly (vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) with different wt% of poly(ethyl methaacrylate) (PEMA) on its electrical properties was studied through AC impedance analysis. The maximum ionic conductivity of 2.14 × 10−2 S/cm at 303 K was found for 5 wt% of PEMA blended film which almost one order higher than the plasticized PVdF-HFP film with no blending (3.15 × 10−3 S/cm). However, blending of 10 wt% of PEMA dropped the conductivity to (5.12 × 10−4 S/cm). This drastic change in conductivity was explained in detail by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) analysis. The dielectric studies showed increase in side chain movements of the host polymer PVdF-HFP for 5 wt% of PEMA blending. However, this segmental motion was found hindered for 10 wt% of PEMA due to steric effect. TG-DTA shows the thermal stability of the plasticized polymer membrane to be increased for the addition of 5 wt% PEMA. Lithium metal polymer cell was made using the optimized blend membrane as an electrolyte with LiV3O8 as cathode and Li metal as anode. The lithium metal polymer cell was found to deliver the specific discharge capacity of 223 mAh/g at the second cycle.