Super strong, shear resistant, and highly elastic lamellar structured ceramic nanofibrous aerogels for thermal insulation

Abstract

Advanced ceramic aerogels with ultra-strong mechanical properties and excellent fire resistance are critically required as heat insulators under extreme conditions. Nevertheless, the current use of ceramic aerogels is usually restricted to their brittleness and structural collapse under transient high-temperature environments. Herein, we demonstrate an efficient and scalable method to design a novel lamellar structured ceramic nanofibrous aerogels with ultra-high mechanical strength, superior shear resistance, high elasticity, and good fire resistance through combining silica nanofibers with aluminoborosilicate (AlBSi) matrices. The obtained SiO₂ nanofibrous aerogels (SNFAs) show comprehensive performances of quick recovery from 60% compressive strain, ultra-high strength of beyond 160 kPa at 60% compressive strain, shear strength as high as 21 kPa at 20% recoverable strain, superior compression and shear fatigue resistance, and invariable high elasticity independent of temperature. Furthermore, the trait of the all-ceramic ingredient endows SNFAs with high-temperature tolerance (the maximum temperature up to 1100 °C) and heat insulation performance (the thermal conductivity of 0.0389 W m⁻¹ K⁻¹ at 25 °C). The innovative fabrication of the promising material is likely to offer new perspectives to make ceramic aerogels an ideal material for thermal superinsulation under drastic circumstances.