Impedance-Matchable 3D MXene Sponge/NiFe@NC Heterostructure with Tunable Pores for Efficient Electromagnetic Wave Absorption and Thermal Resistance
The proliferation of 5G/6G communications and radar systems has intensified electromagnetic wave (EMW) leakage, interference, and thermal management challenges. This study presents a 3D MXene sponge/NiFe@NC heterostructure with tunable pore architecture, fabricated by pyrolyzing a polyurethane (PU) foam template uniformly coated with NiFe-decorated Ti3C2Tx MXene nanosheets. The resulting porous dielectric-magnetic network integrates interconnected MXene pathways with uniformly dispersed NiFe@NC nanoparticles, enabling synergistic dielectric-magnetic loss via conduction loss, dipole/interface polarization, and magnetic loss. Precise pore structure design enhances impedance matching and promotes multi-scattering and internal reflection of EMWs. An 'EMW-pore matching' mechanism is proposed, where pore size governs impedance matching at specific frequencies, enabling tunable absorption performance. The optimized absorber achieves a reflection loss (RL) of -67.84 dB, while radar cross-section (RCS) simulations confirm exceptional attenuation and stealth potential. Additionally, the 3D skeleton derived from PU foam confers remarkable thermal resistance and flame retardancy. This pore-regulation strategy provides a scalable route to designing lightweight, broadband, and thermally stable EMW absorbers for next-generation communication and stealth applications.