“Lotus-root-like” porous ZrO2/C nanofibers with excellent flexibility, thermal stability for high-temperature thermal insulation

Carbon nanofibers (CNFs) possess advantages such as high strength, high-temperature resistance, and high extinction coefficient, making them widely used in aerospace, industrial furnaces, and energy fields. However, the high solid thermal conductivity of CNFs limits their application in high-temperature thermal insulation. To address this issue, we propose simultaneously constructing porous structure and introducing low-thermal-conductivity zirconia (ZrO 2 ) nanocrystals into CNFs to prepare “lotus-root-like” porous ZrO 2 /C nanofibers (ZrO 2 /C-NFs). The ZrO 2 /C-NFs achieved ultra-low thermal conductivity of 0.013 W m −1  K −1 at ambient and 0.077 W m −1  K −1 at 1200 °C, representing reductions of 27.8% and 76.7% compared to solid ZrO 2 /C-NF membranes, respectively. In addition, the ZrO 2 /C-NFs exhibited excellent mechanical property and thermal stability. The tensile strength of ZrO 2 /C-NFs membrane was up to ∼2.2 MPa. The mass retention maintains over 85% even heated at 1400 °C in an argon atmosphere. The integrated properties of the ZrO 2 /C-NFs make them have great promising application in the field of high-temperature thermal insulation. This study also provides a novel approach for designing and fabricating high-performance thermal insulation materials.