Hierarchical multi-dimensional nanostructures enabled by Cu/Cu2+-doped MoS2 with synergistic polarization–conduction loss for broadband electromagnetic wave absorption

Abstract

To address the increasing issue of electromagnetic pollution, it is crucial to develop composite materials that combine efficient electromagnetic wave absorption (EMWA) with robust environmental stability. Incorporating multifunctional components and engineering heterogeneous interfaces has proven effective in enhancing both EMWA performance and corrosion resistance. In this study, a hierarchical composite absorber of CNFs@Cu/Cu²⁺-doped MoS₂ (CMS) was designed by tuning copper (Cu) doping and introducing structural defects in MoS₂. The incorporation of Cu significantly enhanced the conductivity of MoS₂ nanosheets grown on the surface of carbon nanofibers (CNFs), while simultaneously inducing carbon defects, sulfur vacancies, and Cu interstitials, thereby generating abundant heterogeneous interfaces. This hierarchical architecture enables synergistic polarization and conduction losses, thereby delivering enhanced EMWA performance. Specifically, the CMS-6 composite achieved a minimum reflection loss (RL_min) of −67.94 dB at a matching thickness of 1.88 mm and exhibited a broad effective absorption bandwidth (EAB) of 5.50 GHz at 1.79 mm. Compared with the undoped CNFs@MoS₂ (MS) counterpart, the required matching thickness was significantly reduced. HFSS simulations further confirmed its strong stealth capability across a wide range of incident angles (−60° < θ < 60°), with a radar cross-section (RCS) reduction below −20 dB m². In addition, CMS-6 demonstrated superior long-term corrosion resistance relative to its precursor materials. This study proposes an effective strategy for tailoring the properties of MoS₂ and provides valuable insights for designing lightweight, high-performance, and corrosion-resistant EMWA materials.