Synergistic Infrared Shading Effects Endowing Core–Shell SiC@C Fibrous Aerogel with Ultrahigh Temperature Resistance and Ultralow Thermal Conductivity

Advanced thermal insulation materials that exhibit exceptional high-temperature stability, ultralight characteristics, and recoverable compressibility under extreme conditions are in increasing demand. Emerging ceramic fibrous aerogels are promising next-generation materials. However, traditional ceramic aerogels exhibit high thermal conductivity and inadequate thermal stability, resulting in catastrophic structural failure at temperatures above 1500 °C. Herein, a novel core-shell SiC@C fibrous aerogel with a 3D interlocked lamellar structure is fabricated by optimizing centrifugal spinning parameters, followed by high-temperature sintering. This ultralight aerogel with a density of 20.5 mg cm^-3 exhibits good flexibility and processability. In addition, the aerogel demonstrates remarkable stability after being treated at 2100 °C for 1 h in argon, or at 1600 °C for 1 h in air, showing unchanged 3D architectures and good compression resilience. The synergistic infrared shading effects of the carbon shell and SiC core endowed this aerogel with record-breaking thermal-insulation performance, achieving an ultralow thermal conductivity of 82.3 mW (m K)^-1 at 1000 °C, lower than most ceramic fibrous aerogels reported to date. These exceptional thermomechanical and thermal-insulation properties make fibrous aerogels prime candidates for providing robust thermal protection under extreme conditions.