Abstract: The development of high-performance electromagnetic interference (EMI) shielding film materials with low reflectivity is imperative to address the pressing issue of secondary electromagnetic pollution caused by radiation leakage. The design of asymmetric gradient structures emerges as an effective strategy to resolve the conflicting objectives of achieving high shielding performance and low reflectivity. In this study, a simple and easily controllable layered vacuum-assisted filtration method was employed to prepare multifunctional composite films with dual electric and magnetic gradients. The high conductivity and abundant surface functional groups of Ti₃C₂T_x MXene were leveraged to create a tightly bonded layer with aramid nanofibers (ANFs), which was used as an electromagnetic wave reflection layer. Conversely, rGO nanosheets with a composition gradient and flake-like SrFe₁₂O₁₉ were used to construct a dual-gradient layer combining conductive and magnetic properties, acting as the anti-reflection layer. This gradient structure has been shown to significantly reduce the incident wave reflection power coefficient and induce an "absorption-reflection-reabsorption" attenuation behavior. The composite film exhibits a thickness of 206 μm, which results in a total shielding performance of 68 dB. A comparison of the reflection power coefficient for waves incident along the conductive gradient direction with that for direct incidence on the highly conductive layer reveals a decrease from 0.99 to 0.55. Furthermore, the composite film displays exceptional tensile strength, Joule heating effects, and infrared thermal camouflage capabilities. This work provides novel insights into the design and fabrication of multifunctional, integrated, low-reflectivity, high-performance EMI shielding materials.

Key words: Electromagnetic shielding, Low reflectivity, Gradient structure, Two-dimensional conductive materials, Hexagonal SrFe₁₂O₁₉