Development of a multifunctional phase change composite film for all-climate thermal management

Radiative cooling is a promising passive and energy-efficient thermal management technology but suffers from low and unstable cooling power density and inability to achieve all-climate thermal management. To address these challenges, a multifunctional phase change composite film (MPCCF) integrating radiative cooling, latent heat storage, thermochromism, and electrothermal conversion is first proposed for efficient all-climate thermal regulation. The MPCCF with a three-layer structure is assembled using a phase inversion method and a coating process. It can adaptively adjust its solar reflectivity in response to ambient temperature, thereby enabling functional switching. Under high temperature environments and solar irradiance of 732 W/m2, the MPCCF achieves sub-ambient cooling of 7.0 °C through the synergistic effect of phase change materials (PCMs) and radiative cooling. In low-temperature environments, it provides continuous and stable heating by harnessing solar absorption and electrothermal conversion. Furthermore, the self-cleaning surface of the MPCCF offers protection against contamination and enhances durability. Unlike conventional radiative cooling systems, the MPCCF enables both effective passive cooling in hot conditions and active heating in cold conditions, achieving all-climate thermal management. This strategy expands the application of PCMs in multifunctional and energy-saving fields and offers valuable insights for the development of advanced energy materials.