Facile preparation of lightweight high-elastic celluous/SiO2 composite aerogel with outstanding thermal insulation performance

Silica aerogel, renowned for its ultra-low thermal conductivity, holds significantpotential as an advanced thermal insulation material. However, its practical application is hindered by limitations in strength and mechanical properties, particularly under harsh, high-temperature conditions, which compromise both mechanical resilience and insulation. To mitigate this, we synthesized silica nanofibers via electrostatic spinning and subsequently crafted thermally and mechanically robust cellulose fiber/silica nanofiber aerogel composites through freeze-drying. The resulting aerogel demonstrates remarkable physical properties: an ultra-lightweight bulk density of 1.3 mg/cm³, low thermal conductivity (47 mW·m⁻¹·K⁻¹ at 1000 °C), and high resilience. The internal fiber network is densely cross-linked, enhancing collapse resistance, structural stability, and rigid support. Mechanical testing revealed a high stress of 0.88 kPa at 80% compressive strain, which reached 1.02 kPa following 900 °C treatment. Thermal stability and insulation tests demonstrated the aerogel’s ability to withstand extreme temperatures (no combustion under a 1,300 °C flame) and maintain effective thermal insulation while retaining good recovery at 600 °C. These findings indicate that the novel aerogel composites surpass traditional ceramic fiber aerogel materials in mechanical and thermal insulation properties at high temperatures, presenting widespread application potential in extreme high-temperature environments.