Ultra-light, flame-retardant nano-TiO2 coated silica-zirconia ceramic fiber aerogel for thermal insulation

In recent years, ceramic fiber aerogel have been one of the most attractive insulating materials due to its low thermal conductivity, excellent mechanical properties and heat resistance. However, the high radiation heat transfer limits its practical application at high temperatures. In this study, a novel SiO₂-ZrO₂ fiber aerogel/TiO₂ composite (SZTFAs) was successfully designed and prepared through an air-assisted electrospinning technique in conjunction with the hydrolysis of TiCl₄. The SZTFAs exhibits anatase TiO₂ nanocoating on the fiber surface. The SZTFAs have low density (14 mg/cm³), good mechanical properties (up to 80% compressive strain, 105.6 KPa), excellent high temperature stability (1200 °C) and fatigue resistance (after 1000 cycles, the maximum stress and Young’s modulus of the SZTFAs remain above 60%) and low thermal conductivity (0.0292 W/(m·K)). After 10 min of exposure to a butane flame, the backside temperature of the SZTFAs was 165 °C, which was approximately 40 °C lower than that of the samples without added TiO₂. Due to the porous layered three-dimensional structure of SiO₂-ZrO₂ fibers aerogel and TiO₂ nanolayer with shielding infrared radiation, the SZTFAs exhibit excellent heat resistance and thermal insulation properties. This study provides a method for developing ceramic fiber aerogels with excellent thermal insulation and mechanical properties at high temperatures.