In situ Mechanical Foaming of Hierarchical Porous MoC for Assembling Ultra‐light, Self‐cleaning, Heat‐insulation, Flame‐retardant, and Infrared‐stealth Device

Molybdenum carbide (MoC) integrated into a carbon matrix, known for its robust interfacial polarization, emerges as a promising ultra‐lightweight EM wave absorber. However, the fabrication of such materials remains a formidable challenge. Herein, a facile and scalable strategy for preparing MoC‐incorporated carbon matrix employing ZnMo‐HZIF foam material through ball‐milling foaming and calcination process as a promising electromagnetic wave materials (EWAMs). In detail, the 3D foam structure reaches impedance matching, and heterogeneous interfaces of N‐doped MoC‐incorporated carbon material (MoC/NC) promote the dipolar/interfacial polarization, confirmed by the hologram. Mo defects induced the charge transfers, displaying an enhanced interfacial polarization. At 15 wt.%, the minimum reflection loss of the obtained sample at 2.5 mm reaches −47.56 dB, and the effective absorption bandwidth spans 4.40 GHz, nearly covering the full X band. Additionally, the assembly device testing demonstrates their excellent self‐cleaning, heat‐insulation, flame retardancy, and infrared stealth properties. This work presents a new perspective on the synergistic effect of structure and components on electromagnetic wave absorption performance and provides a new approach for preparing lightweight and high‐performance MOF‐based electromagnetic wave absorbing materials.