Ultralight Carbon Tube Foam-Derived SiC Nanofibrous Aerogels with Arbitrary Shape, Excellent Rigidity, and Resilience...

Ceramic aerogels are promising high-temperature thermal insulation materials due to their outstanding thermal stability and oxidation resistance. However, restricted by nanoparticle-assembled network structures, conventional ceramic aerogels commonly suffer from inherent brittleness, volume shrinkage, and structural collapse at high temperatures. Here, to overcome such obstacles, 3D ultralight and highly porous carbon tube foams (CTFs) were designed and synthesized as the carbonaceous precursors, where melamine foams were used as the sacrificial templates to form the hollow and thin-wall network structures in the CTFs (density: ∼4.8 mg cm^-3). Then, the arbitrary-shaped silicon carbide (SiC) nanofibrous aerogels (SNFAs) were obtained through a simple chemical vapor deposition (CVD) process on the CTFs. The resulting SNFAs exhibited excellent comprehensive performances: ultralow density (4.2 mg cm^-3) and thermal conductivity (21.3 mW m^-1 K^-1 at room temperature), excellent rigidity (specific modulus: 13.2 kN·m kg^-1), and resilient compressibility. The SNFAs could support over 2100 times their weight without visible deformation. Furthermore, the SNFAs also showed exceptional high-temperature thermal stability, which means that they could withstand 1100 °C in an air atmosphere and 1550 °C in an inert atmosphere. These superior comprehensive performances enable SNFAs to be suitable for thermal insulation in harsh environments.