Decoupling and Dynamic Regulation of Thermal Radiation and Emissivity via an Active/Passive, Environment‐Adaptive Metamaterial for Intelligent Infrared Camouflage

Infrared stealth at elevated temperatures presents a significant challenge, as it necessitates the simultaneous suppression of thermal radiation and adaptive camouflage against diverse environmental backgrounds. However, existing systems often address only one aspect, failing to achieve high‐temperature stealth across varying environments. To overcome this, a novel sandwich‐structured composite is developed herein, which synergistically combines passive thermal management with active emissivity regulation. This integrated system comprises a directionally porous polyimide aerogel with ultralow thermal conductivity (29.7 mW m −1 K −1 ) as the foundational insulating layer, a polyimide/polyethylene glycol phase‐change composite with high latent heat capacity (157.4 J g −1 ) as the intermediate thermal buffer, and an electrochromic device capable of dynamically modulating its infrared emissivity (emissivity contrast Δ ε = 0.69 across 2.5–14 µm bands) via reversible copper electrodeposition as the functional top layer. The composite demonstrates exceptional performance, including a maximum service temperature of up to 300°C and the ability to maintain a radiation temperature as low as 26.2°C on a 200°C hot background. Furthermore, its emissivity can be actively tuned to conform to varying surrounding conditions. This work provides a viable and advanced strategy for the development of intelligent, environment‐adaptive thermal management systems for effective infrared camouflage in demanding and variable scenarios.