Dual‐Mode Film Based on Highly Scattering Nanofibers and Upcycled Chips‐Bags for Year‐Round Thermal Management

Abstract Advanced thermal management is crucial in mitigating the escalating global energy consumption and alleviating associated climatic and environmental issues. Here, a dual‐mode film that integrates solar heating and radiative cooling functionalities for year‐round thermal management is introduced. The cooling side of the film, composed of PCL‐SiO 2 composite nanofibers, exhibits an impressive solar reflection of 0.98 and a mid‐infrared emissivity of 0.91, resulting in sub‐ambient cooling performance under intensive sunlight. Meanwhile, the heating side of the film, based on the ink side of the upcycled chip bags, efficiently harvests thermal energy from sunlight, leading to a temperature rise of 16.5 °C. The cooling and heating modes of the film can be switched by flipping it. With its outstanding optical properties, weathering durability, and switchable heating and cooling modes, the dual‐mode film holds great potential for year‐round energy savings with minimal environmental impact due to its sustainable composition and easy fabrication.