Magnetically Induced Gradient Architectures for Low-Reflectivity Electromagnetic Interference Shielding in Polymer Composites

The rapid advancement of highly integrated electronic systems has substantially increased the demand for polymer-based electromagnetic interference shielding composites that deliver both high shielding effectiveness and low reflectivity to mitigate secondary electromagnetic pollution. Herein, we present a magnetically assisted strategy for fabricating polymer composites with well-defined gradient architectures. Under the external magnetic field, dielectric/magnetic Fe3O4@MXene particles undergo directional migration within the polymer matrix, forming a vertically graded distribution that is further integrated with a conductive silver nanowires substrate. This hierarchical configuration facilitates a synergistic “absorption–reflection–reabsorption” loss mechanism and promotes optimized impedance matching across multiple interfaces. Consequently, the gradient-structured composites exhibit absorption-dominated EMI shielding behavior in the X-band, achieving a total SE of 49.48 dB with an ultralow reflectance of 0.14. Compared to their homogeneous counterparts, the gradient design increases the absorption coefficient by 9.75% and reduces reflection coefficient by 35.93%. These features effectively suppress unwanted electromagnetic reflections and provide an environmentally friendly approach for high-performance polymer-based EMI shielding composites. This study establishes both a conceptual framework and experimental validation for field-induced architectures in next-generation EMI shielding systems, demonstrating a facile quasi-linear gradient strategy that circumvents complex multilayer assembly while enabling continuous impedance matching and enhanced electromagnetic wave attenuation.