Heterogeneous three-dimensional FeSiAl@SiO2@MoS2 composite with a SiO2 wave-transmitting layer for enhanced electromagnetic wave absorption performance

Abstract

In the realm of communication technology, electromagnetic waves (EMWs) pose a growing threat to information security, human health, the natural environment, and military equipment. EMW absorption (EMWA) materials play a crucial role in addressing these concerns by absorbing and dissipating EMWs. However, the absorption performance of the materials is often limited by poor impedance matching, which can be optimized by introducing heterogeneous structures. Herein, FeSiAl@SiO₂@MoS₂—with a three-dimensional core–shell structure—was prepared using the Stöber and hydrothermal methods, and the influence of silica (SiO₂) content on EMWA performance was studied. As a wave-transparent material, SiO₂ can expand the incidence area for EMWs, allowing more EMWs to enter the interior of the absorber, which helps optimize impedance matching and improve EMWA performance. The composite with uniformly dispersed SiO₂ achieved a minimum reflection loss (RL_min) and a maximum effective absorption bandwidth (EAB_max) of −66.8 dB and 5.22 GHz (RL ≤ 10 dB) at 1.96 and 1.86 mm, respectively, covering over 90% of the Ku band (12.4–18 GHz) for satellite broadcasting and satellite communication. In addition, CST simulations verify that the radar cross section (RCS) of the plate and drone models is significantly reduced at 14.24 GHz and 10 GHz respectively. Introducing SiO₂ offers a novel perspective for the design of EMWA materials.