Research progress of biomass cellulose based daytime radiative cooling materials

Radiative cooling is a zero-consumption passive cooling technology, which can realize cooling via infrared radiation, showing great application in mitigating global warming and energy consumption. To date, traditional daytime radiative cooling materials are produced from petroleum, such as photonics, optical metamaterials, inorganic coatings, which are costly, complex to process, and unrenewable. Biomass cellulose show great application in daytime radiative cooling field due to its high infrared emissivity, renewable, and easy processable property. In this paper, based on the fundamental principle of radiative cooling, the physical and optical mechanism of daytime radiative cooling was firstly discussed. We divided the cellulose based daytime radiative cooling materials into cooling films, cooling fabrics, cooling aerogels, and cooling structural materials based on the structure and morphology. We also elucidated the mechanism of the influence of different structures of cellulose on the daytime radiative cooling performance at the micro and nano scales. Finally, the future research and development direction of cellulose-based radiative cooling materials are discussed: The biomass based daytime radiative cooling materials with high cooling power and dynamic/smart function is highly demanded in the future.