Polymer Template Synthesis of Flexible SiO2 Nanofibers to Upgrade Composite Electrolytes

Flexible oxide ceramic films offer prospects for revolutionizing diverse fields such as energy and electronics, but their fabrication methods are typically elaborate and cannot be expanded. Here, we report a scalable strategy to fabricate flexible and robust SiO2 nanofiber films with controllable morphology using a sol–gel electrospinning method followed by low-temperature calcination. When applied to composite polymer electrolytes (CPEs) for solid-state batteries by filling polyethylene oxide into porous ceramic films, SiO2 nanofibers with large surface areas (51 m2·g–1) demonstrate strong Lewis interfacial interactions and isotropic ionic transfer channels that mitigate polymer crystallinity and Li+-concentration polarization, imparting high conductivity (1.3 × 10–4 S·cm–1 at 30 °C) and structural stability to the electrolytes. As a result, all-solid-state LiFePO4||Li shows great rate capability and long cycling stability with high discharge capacities of 159 and 132 mA·h·g–1 at 0.5C under 60 and 45 °C, respectively, demonstrating broad commercial prospects for the scale production of efficient solid electrolytes.