Composite polymer electrolytes (CPEs) based on polyethylene oxide (PEO) offer manufacturing feasibility and outstanding mechanical flexibility. However, the low ionic conductivity of the CPEs at room temperature, as well as the poor mechanical properties, have hindered their commercialization. In this work, Solid-state electrolytes based on polyethylene oxide (PEO) with and without fumed SiO2 (FS) nanoparticles are prepared by electrostatic spinning process. The as-spun PEO hybrid nanofiber electrolyte with 6.85 wt% FS has a relatively high lithium ion conductivity and electrochemical stability, which is 4.8 × 10-4 S/cm and up to 5.2 V vs. Li+/Li, respectively. Furthermore, it also shows a higher tensile strength (2.03 MPa) with % elongation at break (561.8). Due to the superior electrochemical and mechanical properties, it is promising as high-safety and all-solid-state polymer electrolyte for advanced Li-metal 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 S·cm−1 (χ(SiO 2/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.