Flexible porous SiZrOC ultrafine fibers for high-temperature thermal insulation

• The PSUF with high flexibility and thermal stability were firstly prepared by electrospinning technique. • The unique porous structure endowed the PSUF with better thermal insulation performance than the SSUF. • The thermal insulation mechanisms of the PSUF were clarified. • The flexible PSUF showed great potential as thermal insulators under extreme conditions. Ceramic fibers with combined properties of high flexibility, thermal stability and thermal insulation performance are attractive for use in extreme conditions. In this work, the porous SiZrOC ultrafine fiber (PSUF) composed of SiO 2 , ZrO 2 , SiO x C y and free carbon phases was firstly prepared by electrospinning technique. The resulting PSUF exhibited integrated properties of high flexibility and high-temperature stability. More importantly, comparing with solid SiZrOC fiber, the fancy porous structure made the thermal conductivity of PSUF decreased 16.6% to 0.141 W m −1 ·K −1 at 1000 °C. The successful fabrication of such flexible PSUF may provide a new approach to design high performance thermal insulators for high-temperature thermal insulation.