Super-insulating, ultralight and high-strength mullite-based nanofiber composite aerogels

Ceramic nanofiber aerogel is one of the most attractive insulation materials in recent years. However, its practical application ability is limited at high temperature due to high radiation heat transfer. Herein, we constructed a novel closed-cell/nanowire structured mullite-based nanofiber composite aerogel via electro-spinning technology and solvothermal synthesis method. Hollow TiO2 spheres were used as pore-making material and infrared opacifier to reduce fiber solid heat conduction and high temperature radiation heat transfer simultaneously. In addition, TiO2 nanowires grown in-situ on the fiber surface further decrease the radiation heat transfer of aerogel and improve the mechanical properties. The unique structure endows the aerogel with high mechanical robustness (0.32-0.35 MPa, 10% strain), low density (39.2-47.5 mg/cm(3)) and ultralow thermal conductivity (-0.017 W m(-1 )K(-1) at 25 degrees C and-0.056 W m(-1) K-1 at 1000 degrees C). This work offers a novel strategy for the development of ceramic nanofiber aerogel at high temperature.

Automated summary

This study successfully developed a novel closed-cell/nanowire structured ceramic nanofiber aerogel by combining electro-spinning technology and solvothermal synthesis method. By using hollow TiO2 spheres as pore-making material and infrared opacifier, and incorporating in-situ grown TiO2 nanowires on the fiber surface, the aerogel exhibits high mechanical robustness, low density, and ultralow thermal conductivity.