Robust fluorinated cellulose composite aerogels incorporating radiative cooling and thermal insulation for regionally adaptable building thermal management.

Passive radiative cooling (PRC) is an emerging sustainable technology that plays a key role for achieving the goal of carbon neutrality. However, several challenges remain for PRC materials in their practical application in building thermal management, including overcooling problems and unsatisfactory cooling efficiency caused by solar absorption and parasitic heat gains. In this work, fluorinated cellulose-based composite aerogels (FCCA) integrating thermal insulation and PRC were developed by a facile manufacturing strategy that combined phase separation and freeze-drying. P(VdF-HFP) was utilized to promote the formation of nano/micro porous architectures in FCCA, resulting in a decrease in the thermal conductivity of the aerogel to 0.034 W m K while simultaneously increasing its solar reflectance and infrared emissivity (8-13 μm) to 95.74 % and 97.15 %, respectively. The aerogel cooler achieved a sub-ambient cooling temperature of ∼9.68 °C during the daytime and maintained its cooling effectiveness even on cloudy days. The fluorinated aerogels demonstrated excellent hydrophobicity and chemical durability after outdoor exposure and heat aging tests. This work opens up a new pathway to design low-cost cellulose-based materials for efficient thermal management of energy-saving buildings around the world.