Facile fabrication of graphite-doped silica aerogels with ultralow thermal conductivity by precise control

Graphite-doped silica (G/SiO2) aerogels for thermal insulation were prepared through doping colloidal graphite (G) into silica (SiO2) sol, followed by aging, washing and supercritical drying. The morphology and structure of the as-prepared composite aerogels were characterized by means of scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrum, and nitrogen adsorption/desorption measurement. It was found that all the composite aerogels had the typical three-dimensional porous structure and high specific surface areas (~ 1500 m2/g). The thermal conductive property of the composite aerogels was studied by SHT-P transient automatic measurement. The results indicated that the thermal conductivity of the G/SiO2 composite aerogel with G/SiO2 mass ratio of 0.4% was 0.017 W/(m·K) at room temperature, which was lower than that of pure SiO2 aerogel (0.02 W/(m·K)) and endowed the G/SiO2 composite aerogel good thermal insulation performance.