Enhanced mechanical strength and conductivity of PVFM based membrane and its supporting polymer electrolytes

ABSTRACT Polyvinyl formal based polymer electrolyte membranes are prepared via the optimized phase inversion method with poly(ethylene oxide) (PEO) blending. The physical properties of blend membranes and the electrochemical properties of corresponding gel polymer electrolytes (GPEs) are characterized by field emission scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, mechanical strength test, electrolyte uptake test, AC impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge test. The comparative study shows that the appearance of PEO obviously enhances the tensile strength of membranes and the ionic conductivity of corresponding GPEs. When the weight ratio of PEO is 30%, the tensile strength of membrane achieves 12.81 MPa, and its GPE shows high ionic conductivity of 2.20 × 10−3 S cm−1, wide electrochemical stable window of 1.9–5.7 V (vs. Li/Li+), and good compatibility with LiFePO4 electrode. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41839.