All-In-One Thermal Protection: Multifunctional Synergy in Hierarchically Structured Dual-Oxide Nanofiber Aerogel

Ceramic nanofiber aerogels are emerging as promising thermal protection materials, yet their brittleness remains a critical challenge. This work designs a hierarchical fibrous aerogel consisting of streamlined dual-oxide nanofibers featuring a dense-sheath/porous-core architecture, simultaneously overcoming the intrinsic fragility while enabling thermal-protection. The obtained aerogel demonstrates ultra-low thermal conductivity and exceptional thermomechanical stability a high working temperatures. The aerogel structure, constructed from arbitrarily bendable nanofibers, reduces the overall density and effectively lowers thermal conductivity. The minimum density can reach as low as 8 mg·cm^-3. This unique structure enhances the mechanical stability of the entire aerogel in a wide working temperature (-196 to 1300 °C) upon 80% compression. The thermal conductivity achieves an extremely low value of 7 mW·m^-1·K^-1. These attributes originate from the following mechanisms: depressing heat transfer by prolonging heat conduction pathways and offering interfacial insulation, while impeding phonon transport within nanopores. Upon simulated space-ground integrated experiments at ≈1200 °C, the ceramic nanofiber aerogel exhibits remarkable resistance to thermal vibration. The nanofiber aerogel can serve as an all-in-one platform to synergistically integrate noise absorption and catalytic conversion, thereby paving the way for future practical applications.