Ceramic fiber aerogels are highly desirable for extreme thermal protection due to their ultralight weight and superior insulation. However, their sparse skeleton often suffers from high radiative heat transfer and structural fragility, leading to catastrophic failure under intense heat flux. Here, a robust hierarchical structure is constructed via the in situ growth of TiO₂ nanowires (TNWs) on mullite nanofiber (MNF) aerogels to systematically enhance high-energy laser ablation resistance. This multiscale design significantly improves reflectivity from 94.68% to 97.25% and reduces light absorption by 48.3%, effectively mitigating laser ablation damage through high reflection and scattering efficiency. The MNF-TNW aerogels also exhibit superior thermal management, showing 30.8% lower thermal conductivity at 1000 and a 51.3 °C lower back temperature under flame exposure than conventional MNF aerogels. Under high-energy laser ablation at 300  W·cm⁻², the MNF aerogels fail within 3  s, whereas the MNF-TNW aerogels withstand 30  s of ablation and repeated impacts. Even at 500  W·cm⁻² for 30  s, no significant damage occurs. Therefore, this in situ growth strategy offers a promising avenue for engineering high-performance ceramic aerogels for applications in extreme environments.

Mullite nanofiber aerogels (MNAs) exhibit promising potential for application in the thermal protection systems of hypersonic vehicles. However, the sharp increase in high-temperature thermal conductivity and limited functionality hinder their further development. Herein, hierarchical mullite/SiC nanofiber composite aerogels (MSNCAs) are constructed based on SiC hollow spheres and SiC nanowires, achieving multifunctional integration of infrared shielding and strong electromagnetic wave (EMW) absorption. SiC hollow spheres serve as closed-cell units to create a porous fiber skeleton, whereas SiC nanowires form a secondary reinforcing network between the fibers. Their synergistic effect endows MSNCAs with excellent infrared shielding and EMW absorption performance. The composite exhibits a thermal conductivity of only 0.0516  W/(m·K) at 1000 °C and achieves a reduction of 61.54% in infrared transmittance between 2.5 and 8 μm, demonstrating efficient high-temperature insulation. Moreover, the multiscale structure optimizes impedance matching and enhances dielectric loss. Consequently, MSNCA-15 exhibits a reflection loss of −54.85 dB with an effective absorption bandwidth of 4.88 GHz at a thickness of 1.8 mm. Simultaneously, the bridging effect of SiC nanowires improves the compressive strength of the aerogel to 0.41 MPa. This study provides a new structural design strategy for developing lightweight composite materials that feature efficient thermal insulation and electromagnetic stealth properties.

Silicon carbide (SiC) fiber aerogels are promising materials for renewable energy and aerospace applications. However, conventional SiC aerogels often suffer from limitations such as single-pore structures, inadequate mechanical strength, and high production costs, which severely restrict their practical application. Here, we designed and fabricated a hierarchical porous SiC microtube/nanowire composite aerogel derived from kapok fibers via an in situ conversion strategy. This approach directly utilizes kapok hollow fibers to construct SiC microtubules while simultaneously inducing the self-growth of SiC nanowires, achieving controllable hierarchical pore fabrication in a single step. Compared with conventional methods, this strategy significantly simplifies the fabrication process and enhances multifunctional performance through structural synergy. The unique microtube-nanowire heterostructure provides excellent electromagnetic wave (EMW) absorption (minimum reflection loss (RL) of −56.39 dB, effective absorption bandwidth of 6.04 GHz at 2.0 mm) by enhancing interfacial polarization and optimizing impedance matching. The nanowire bridging effect achieves a compressive strength of 2.85 MPa, surpassing the mechanical limits of conventional aerogels. Additionally, the aerogel exhibited excellent thermal insulation (0.021 W·m⁻¹·K⁻¹) and pollutant adsorption capacity (45–67 times its weight). This research offers a new approach for developing high-strength, multifunctional SiC aerogels.