Ambient-freeze hybrid drying: A facile, low-cost synthesis method for composite silica aerogel with ideal formability and thermal insulation performance

Due to the fragile characteristic of silica aerogel, it is difficult to achieve large-scale preparation of large-sized and multi-shaped silica aerogels through the simple and low-cost ambient drying method to meet the needs of various application fields. In this study, we present a novel approach that combines ambient and freeze drying methods to synthesize fiber composite silica aerogels with excellent formability and thermal insulation performance. Rock-wool fibers and TiO 2 /ZrO 2 fibers produced by electrostatic spinning were employed to fabricate composite in various shapes. The rock-wool fiber composite aerogel exhibits high thermal insulation performance with a thermal conductivity of 0.0283 W m −1  K −1 at room temperature. The TiO 2 /ZrO 2 fiber composite aerogel demonstrates a high specific surface area of 792.26 m 2  g −1 and outstanding temperature resistance up to 800 °C. The Mie scattering simulations demonstrate that the TiO 2 /ZrO 2 composite fibers exhibit high radiative shielding properties at high temperature and the measured thermal conductivity of the TiO 2 /ZrO 2 fiber composite aerogel powder is 0.0538 W m −1  K −1 at 800 °C in an argon atmosphere. This study introduces a novel method for integrating silica aerogel with various types of fibers, expanding the potential applications of ambient drying aerogels.