Scalable Fabrication of Y3+-Doped Silica-based Multiphase Nanofibers for High-Performance Thermal Insulation Applications

Silica nanofibers often suffer from structural collapse at elevated temperatures, limiting their high-temperature applications. To address this challenge, we develop a novel multiphase nanofibers system by incorporating yttrium silicate nanocrystals into an amorphous SiO 2 matrix. Through precise control of the SiO 2 /Y 2 O 3 molar ratio, optimized nanofibers are fabricated via electrospinning combined with a sol-gel process. Comprehensive characterization (XRD, SEM, XPS, BET and TEM) confirmed the formation of a homogeneous composite structure, with the 7:1 SiO 2 /Y 2 O 3 molar ratio exhibiting optimal performance. The resulting nanofibers demonstrate significantly enhanced thermal stability compared to pure SiO 2 fibers, maintaining structural integrity at temperatures up to 1300 °C. Furthermore, the composite nanofibers exhibit superior thermal insulation property, with a thermal conductivity of only 0.122 W·m -1 ·K -1 at 1000 °C. Flame exposure tests reveal exceptional heat resistance, with the backside temperature remaining below 67 °C despite direct 1300 °C flame impingement. This work provides a promising strategy for designing high-performance thermal insulation materials for extreme environments.