Mechanically Robust Ceramic Aerogels for Radiative Cooling and Thermal Insulation

Abstract

ABSTRACT Cooling and heating consume about half of global energy and result in various environmental problems. Radiative cooling and thermal insulation can reduce energy consumption, yet the existing materials that integrate both properties have limitations in working temperature range and mechanical robustness. Herein, we report a flexible and ultralow‐density HfO 2 ‐ZrO 2 ‐SiO 2 ceramic aerogel fabricated via a modified electrospinning method, which synergistically integrates radiative cooling, thermal insulation, mechanical robustness, and an ultrawide temperature range. It achieves high solar reflectance (98.0%) and high infrared emittance (98.4%) for daytime radiative cooling, along with ultralow thermal conductivity (24.7 mW m −1  K −1 at 2.58 mg cm −3 ), enabling 24‐hour thermal insulation. It also exhibits excellent mechanical properties at 7.50 mg cm −3 , including 245 kPa tensile strength, 1.47 MPa compressive strength, and 182 kPa bending strength, along with an ultrawide working temperature range from −196°C to 1300°C. Moreover, in lunar environment simulation experiments, our aerogel achieves ∼50.0°C cooling below ambient during the day and ∼37.5°C thermal retention above ambient at night, successfully maintaining electronics above −16.7°C in an ambient temperature of −183°C. This work provides a mechanically robust ceramic aerogel solution for low‐energy consumption, 24‐hour thermal management in aerospace, deep‐space exploration, and high‐precision instruments.