Synergistic Fe─Ni Diatomic Sites Engineered in Hierarchically Porous Carbon Fibers for Integrated Microwave and Infrared Multi‑Spectrum Stealth

ABSTRACT Environmentally adaptive multi‐band electromagnetic response materials, encompassing microwave absorption and infrared stealth, hold significant potential for military and civilian applications. However, developing such multifunctional materials remains challenging due to the distinct response mechanisms of electromagnetic waves across different frequency bands. Herein, we report a porous foam composed of 1D porous carbon fiber anchored with Fe─Ni heteronuclear diatomic sites and organic polyurethane, which exhibits outstanding microwave absorption and infrared stealth properties as well as environmental adaptability. The foam achieves an efficient microwave absorption bandwidth of 8.32 GHz, and a low thermal conductivity of 0.36 W m −1 K −1 , surpassing most reported absorbers. Experimental and theoretical analyses demonstrate that synergistic enhancements of conductive and polarization losses by Fe─Ni diatomic sites contribute to the microwave absorption performance, while infrared stealth originates from the low inherent thermal conductivity of the polyurethane matrix and porous structure within the foam. The foam also displays excellent mechanical strength, compression resilience, hydrophobicity, and salt corrosion resistance, thereby broadening its applicability. This work provides a viable approach for developing new‐generation, environmentally adaptive, wide‐band electromagnetic protection materials through cross‐scale precision design and multi‐functional synergistic integration.