Investigation of structure and ionic conductivity of (PEO)12-SiO2-LiClO4 nanocomposite electrolyte for all solid-state lithium-ion battery

Solid polymer electrolytes (SPEs), based on poly ethylene oxide (PEO) matrix and nano-sized SiO2, are prepared by solution-casting method. The morphology, crystallinity, thermostability and ionic conductivity of nanocomposite polymer electrolyte are systematically investigated by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis, and AC impedance spectroscopy. The result reveals that SiO2 is uniformly dispersed in the SPE. Furthermore, the incorporation of nano-sized SiO2 can restrict the crystalline behaviour of PEO effectively, leading to the improvement in amorphous state of PEO. With increasing the mass loading of SiO2, the ionic conductivity of SPEs increase to a maximum value, about 3.03 × 10−4 Scm−1 (χ(SiO2/PEO) = 6.85%), and then fall down. Meanwhile, the initial decomposition of SPE reaches 335 °C, showing the good thermal stability and potential application of SPEs for the next-generation all solid-state lithium-ion battery (LIB) with enhanced safety.