Simultaneous enhancement of the mechanical and thermal insulation properties of carbon nanofibres by in-situ embedding of ZrO2 nanocrystals

Carbon nanofibres (NFs) are promising high-temperature thermal insulators, but their performance is limited by their high solid thermal conductivities. Although ultrafine, hollow or porous structures can effectively reduce the thermal conductivity, they introduce structural defects that significantly decrease the mechanical properties. To overcome this limitation, we present the ZrO 2 /C NFs prepared using polyacrylonitrile (carbon source) and Zr(SO 4 ) 2 (Zr source) via electrospinning combined with precursor conversion technology and in-situ embedding of ZrO 2 nanocrystals with low solid thermal conductivity in polyacrylonitrile-derived carbon NFs. The ZrO 2 /C NF membranes achieve low thermal conductivities of 0.018 W·m -1 ·K -1 and 0.331 W·m -1 ·K -1 at the ambient temperature and 1200 °C, 64.0% and 40.6% less than those of the carbon NFs, respectively. They also retain remarkable flexibility, high tensile strength (∼1.86 MPa) and thermal stability even after heat treatment at 1200 °C. This work presents a novel approach for the design and fabrication of similar high-performance thermal insulating materials.