Embedding Multiple Magnetic Components in Carbon Nanostructures via Metal‐Oxo Cluster Precursor for High‐Efficiency Low‐/Middle‐Frequency Electromagnetic Wave Absorption

With the advent of wireless technology, magnetic-carbon composites with strong electromagnetic wave (EMW) absorption capability in low-/middle-frequency range are highly desirable. However, it remains challenging for rational construction of such absorbers bearing multiple magnetic components that show uniform distribution and favorable magnetic loss. Herein, a facile metal-oxo cluster (MOC) precursor strategy is presented to produce high-efficiency magnetic carbon composites. Nanosized MOC Fe₁₅ shelled with organic ligands is employed as a novel magnetic precursor, thus allowing in situ formation and uniform deposition of multicomponent magnetic Fe/Fe₃O₄@Fe₃C and Fe/Fe₃O₄ nanoparticles on graphene oxides (GOs) and carbon nanotubes (CNTs), respectively. Owing to the good dispersity and efficient magnetic-dielectric synergy, quaternary Fe/Fe₃O₄@Fe₃C-GO exhibits strong low-frequency absorption with RL_min of -53.5 dB at C-band and absorption bandwidth covering 3.44 GHz, while ultrahigh RL_min of -73.2 dB is achieved at X-band for ternary Fe/Fe₃O₄-CNT. The high performance for quaternary and ternary composites is further supported by the optimal specific EMW absorption performance (-15.7 dB mm^-1 and -31.8 dB mm^-1) and radar cross-section reduction (21.72 dB m² and 34.37 dB m²). This work provides a new avenue for developing lightweight low-/middle-frequency EMW absorbers, and will inspire the investigation of more advanced EMW absorbers with multiple magnetic components and regulated microstructures.