Structural Design of Lightweight Core–Shell FeCo@C Nanoparticles/Ti ₃ C ₂ T _x MXene Composite toward Excellent Microwave Absorption

Layered MXene-based magnetoelectric composites have been extensively investigated and applied as microwave absorbing (MA) materials. Although multicomponent composite strategies have been proven to significantly improve the MA performance of materials, the fine structural design and optimization of the functional synergy of absorbers at intricate environments remain scientific issues worthy of further exploration. In this study, FeCo@C/Ti 3 C 2 T x MXene composites were synthesized through a combination of chemical vapor deposition and electrostatic self-assembly techniques. The core–shell structure of ultrafine FeCo@C nanoparticles, with an average diameter of 13.51 nm, has effectively mitigated the adverse effects of harsh environmental conditions due to chemical stability of the carbon layer. Furthermore, the integration of ultrafine FeCo@C nanoparticles with a low filler loading contributed to the overall lightweight characteristic. Notably, the FeCo@C/Ti 3 C 2 T x MXene composites with a 20 wt % filling ratio exhibit a minimum reflection loss ( RL min ) of −31.6 dB at 1.7 mm and an effective absorption bandwidth of 5.76 GHz at 2.4 mm. The corresponding absorbing coating achieves a maximum reduction in the radar cross-section of 18.86 dBm 2 . The FeCo@C/Ti 3 C 2 T x MXene composites exhibit the potential for applications in challenging environments, including high-temperature and humid conditions.