Synthesis of flexible, strong, and lightweight oxide ceramic nanofibers via direct electrospinning of inorganic sol for thermal insulation

Oxide ceramic nanofibers are widely used in aerospace and civil facilities due to their superior thermal stability and fire resistance. Currently, electrospinning, one of the important methods for preparing oxide ceramic nanofibers, must rely on adding organic polymers to impart spinnability to inorganic sols. However, these organic polymers will inevitably leave hole flaws in the ceramic nanofibers due to thermal decomposition during the subsequent ceramization process, seriously damaging their mechanical properties. Here, a direct electrospinning strategy for inorganic sol through hydrolyzation–polycondensation rate modulation is proposed, which gets rid of the dependence of spinnability of inorganic sol on organic polymer. Taking silica nanofibers as an example, it exhibits excellent flexibility and mechanical strength (tensile stress up to 1.4 MPa), as well as thermal insulation properties (thermal conductivity as low as 0.0551 W m−1 K−1 at 300 °C). This work provides new insights into developing other high–performance oxide ceramic materials.