Orbital hybridization induced polarization loss for broadband electromagnetic wave absorption

Orbital hybridization has proven to be an effective strategy for tailoring electromagnetic wave absorption (EMWA) performance. However, achieving precise control over such hybridization remains challenging. In this study, spherical NiTe@NC (NTC) composites were synthesized through a combined hydrothermal method, polymerization reaction, and high-temperature tellurization. By varying the mass ratio of nickel-based metal-organic framework (Ni-MOF) to polydopamine (PDA), the EMWA performance of the composite was adjusted. At an optimal Ni-MOF to PDA mass ratio of 1:4 and a filler loading of 30 wt.%, the composite exhibits a minimum reflection loss (RL_min) value of −30.66 dB at a thickness of 1.73 mm and achieved an effective absorption bandwidth (EAB) value of 6.80 GHz at 1.96 mm. The Density functional theory (DFT) results confirm strong d-p orbital hybridization between the Ni 3d, Te 5p, and N 2p orbitals. The excellent EMWA capability stems from the synergistic combination of conductive loss, polarization loss, and magnetic loss. Furthermore, by designing a gradient multilayer periodic array based on NTC, the EAB could be broadened to 12.72 GHz (5.28–18 GHz). Radar cross-section (RCS) simulation results show that the RCS of the NTC-2 composite is reduced by 19.06 dB·m² compared with that of a perfect electric conductor. Overall, this work provides insights into the development of hybridization induced broadband EMWA materials.