Physicochemical properties of a novel composite polymer electrolyte doped with vinyltrimethoxylsilane-modified nano-La2O3

Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) based composite polymer electrolyte doped with the modified nano-La2O3 was prepared by phase inversion method. The physicochemical properties were studied by SEM, FT-IR, XRD, TG and electrochemical methods. The results of FT-IR indicated that the nano-La2O3 was successfully modified with vinyltrimethoxylsilane. The XRD analysis showed that the incorporation of modified nano-La2O3 into the polymer electrolyte membranes could effectively reduce the crystallinity of PVDF-HFP, and the characterizations also suggested that thermal stability and electrochemical stability window could reach to 382 °C and 5.1 V, respectively; the reciprocal temperature dependence of ionic conductivity followed Vogel-Tamman-Fulcher (VTF) relation, ionic conductivity at room temperature was up to 3.5×10−3 S/cm and lithium ions transference number was up to 0.42; the interfacial resistance increased at initial value about 353 O/cm2 and reached a steady value about 559 O/cm2 after 5 d storage at 30 °C. The fabricated Li/As-prepared electrolytes/LiCoO2 coin cell showed excellent rate and cycle performances.