Mie‐Resonant Thermochromic Safe Architectures for All‐Season Radiative Thermal Management

ABSTRACT Intensifying extreme weather increasingly exacerbates solar heating loads, leading to higher energy consumption, environmental stress, and thermal discomfort in urban and transportation settings. While passive radiative cooling offers a sustainable mitigation strategy, conventional materials suffer from static optical properties that lead to winter over‐cooling and poor seasonal adaptability. To overcome these limitations, we present a scalable, seasonally adaptive thermochromic composite film (TCF) capable of autonomous bidirectional thermal regulation. By embedding size‐optimized thermochromic microcapsules into a hierarchical porous poly(vinylidene fluoride‐co‐hexafluoropropylene) matrix, we engineer microstructure‐dependent Mie scattering to effectively decouple visible–near‐infrared (vis–NIR) modulation from long‐wave infrared (LWIR) emission. This architecture enables the TCF to reversibly switch between a solar‐absorbing heating state and a solar‐reflecting cooling state while maintaining high atmospheric‐window emissivity via impedance matching, achieving heating of ≈245 W/m 2 and cooling of ≈86 W/m 2 . Outdoor testing demonstrates stable cooling/heating capability and durability over 180 days. Produced via a scalable, meter‐scale continuous process, the TCF can be applied as a radiative‐cooling coating or integrated into functional textiles, providing year‐round adaptability for buildings, vehicles, and wearable systems. Overall, this work outlines a practical strategy for intelligent, energy‐saving materials capable of dynamically balancing heating and cooling for sustainable thermal management.