Reconciling Impedance Matching and Attenuation Capability in CNF@MoS2@NiFe2O4 Absorbers for Efficient Electromagnetic Dissipation

Balancing impedance matching and attenuation capability remains a key challenge for electromagnetic wave absorbers. In this work, a ternary hierarchical carbon nanofiber @MoS2@NiFe2O4 (CMN) composite was successfully fabricated via a facile two-step hydrothermal method. By adjusting the NiFe2O4 loading, a series of composites (CMN-0.2, CMN-0.4, and CMN-0.6) were obtained. The unique hierarchical structure integrates highly conductive CNF as conductive networks and vertically grown MoS2 nanosheets that supply abundant heterogeneous interfaces and defect sites, while uniformly anchored NiFe2O4 nanoparticles are introduced to tune electromagnetic parameters and optimize impedance matching. The formation of CNF/MoS2 Schottky heterojunction and MoS2/NiFe2O4 p-n heterojunction generates dual built-in electric fields, which effectively promote interfacial charge separation and enhance polarization loss. Electromagnetic wave absorption properties analysis reveals that the CMN 0.4 sample achieves the optimal trade off between favourable impedance matching and attenuation capacity. It exhibits an excellent minimum reflection loss of -61.6 dB at an ultra-thin matching thickness of only 1.7 mm and a maximum effective absorption bandwidth of 5.04 GHz. Radar cross-section simulation further demonstrates a maximum reduction of 32.7 dB·m2 compared to a perfect electric conductor at 0º, highlighting its outstanding radar stealth capability. The superior performance is attributed to the synergistic effects of impedance matching, conductive loss, interfacial and dipolar polarization.