Preparation, characterization, conductivity studies of novel solid polymer electrolytes based on blend of poly (AN-co-VEC) and EVA

Novel solid polymer electrolytes (named as SRx (x = 1–6)) containing trifluoromethane sulfonates (LiCF3SO3) are prepared based on the blend of poly (acrylonitrile-co-vinyl ethylene carbonate) poly (AN-co-VEC) and ethylene vinyl acetate copolymer (EVA). The structural properties of the polymer electrolytes SRx are systematically investigated by varieties of techniques, and the electrochemical performance including ion conductivity and Li+ transference number are studied by electrochemical impedance spectroscopy (EIS). The surface morphology of solid polymer electrolyte are subjected to transmission electron microscopy (TEM) and scanning electron microscopy (SEM) measurements, by which highly collected spherical grains are found on the picture of SEM and TEM. It is noteworthy that the special structure probably affords fast transport paths for Li+, enhancing ionic conductivity (= 6.0 × 10− 5 S cm− 1) and Li+ transference number (t+ = 0.74), and the former is higher than that of conventional solid polymer electrolytes which is up to now mostly 10− 7 to 10− 8. The reason may be due to excellent solubility of VEC for Li+ salt, besides, the spherical structure of the solid polymer electrolyte may play an important role. This is perhaps the first report of VEC used as host copolymer for the solid polymer electrolytes.