FeCl₃-Intercalated Carbon Nanotube Film for Long-Term Infrared Camouflage in Harsh Environments

Infrared camouflage, realized by engineering temperature and spectral emission characteristics, is crucial in various scientific and engineering fields. Yet, a significant challenge lies in fabricating advanced functional materials that can durably maintain infrared camouflage performance under harsh operational conditions. Herein, we report a FeCl₃-intercalated carbon nanotube (CNT) film fabricated via a vapor intercalation strategy, with FeCl₃ molecules inserted into the interlayer spacing of the CNT. Compared with pristine CNT, the FeCl₃-intercalated CNT composite demonstrates significantly enhanced infrared camouflage capabilities, exhibiting apparent temperature variations of +16.7 °C, -6.6 °C, and -144 °C relative to the CNT film, under low (-4 °C), body (34.3 °C), and high (300 °C) temperature backgrounds, respectively. Moreover, extensive durability tests involving heat, insolation, and rain have confirmed the unaltered infrared camouflage performance of the FeCl₃-CNT film. The performance enhancement is attributed to the suppressed infrared absorptivity across the 2.5-15.2 μm wavelength range, with a pronounced reduction from 72% to 30% at 15 μm, driven by intercalation-induced charge transfer and the consequent Fermi energy (E_F) shift. This work presents a promising approach for designing advanced functional materials to achieve long-term infrared camouflage in complex environments.