Scalable Low-Carbon Ambient-Dried Foam-Like Aerogels for Radiative Cooling with Extreme Environmental Resistance.

Aerogels have emerged as promising passive radiant cooling materials, offering a sustainable solution to mitigate global warming. However, the energy- and resource-intensive fabrication processes and insufficient environmental durability of current aerogels pose significant challenges for industrial scalability and long-term energy-saving applications. Here, a scalable low-carbon ambient-dried foam-like aerogel (GMSx) with integrated radiative cooling and fire/harsh-conditions resistance is reported. Thermoresponsive physicochemical interactions among gellan gum, melamine-formaldehyde resin, and fumed silica facilitate the transformation of scalable emulsion-templated hydrogels into structurally ordered GMSx via a green ambient-drying process without complex freezing and solvent exchange. The foam-like aerogel exhibits high porosity (96.2%) and record specific modulus (323 m/s). Optimized optical properties with 93% solar reflectance and 94% infrared emissivity yield subambient cooling of 4.8 °C. Crucially, the robust crosslinked networks impart remarkable durability under extreme conditions, including exposure to hot water, strong acids/alkalis (pH 1-13), various chemicals, and 1300 °C flame. Furthermore, GMSx can be customized into various shapes via extrusion or spraying techniques and applied as protective coatings using scalable brushing or dipping methods, accommodating diverse substrate geometries. This work overcomes critical scalable green fabrication and durability challenges in passive cooling aerogels, demonstrating practical potential for energy-efficient thermal management in harsh environments.