Cascaded Heteroporous Nanocomposites for Thermo‐Adaptive Passive Radiation Cooling

Abstract Passive radiative cooling is a promising technology for heat dissipation that does not consume energy. However, current radiative cooling materials can only exhibit subambient cooling under atmospheric conditions and struggle to process specific heat accumulation. Thus, a passive thermal regulation mechanism adapted to wide‐temperature‐range applications is required to match device heating systems. Herein, a heteroporous nanocomposite film (HENF) with thermo‐adaptive radiation cooling performance is reported. Compared to conventional porous cooling films with limited scattering efficiencies, the HENFs with multistage scattering have a strong emissivity of 96.5% (8–13 µm) and a high reflectivity of 97.3% (0.3–2.5 µm), resulting in an ultrahigh cooling power of 114 W m −2 . In such HENFs, theoretical analyses have confirmed the spectrum management superiority of the heteroporous unit in terms of the scattering efficiency strength, with their cascading effect enhancing the overall film‐cooling efficiency. The high mechanical performance, phase‐transition features, and environmental adaptive properties of HENFs are also exhibited. Importantly, HENFs synergistically couple thermal dissipation and absorption to effectively process heat accumulation and counteract thermal shock in heating devices. It is anticipated that thermo‐adaptive HENFs will act as a promising platform for device surface thermal regulation over a wide temperature range.