Gradient network structure of Fe3O4@MnO2/AgNW composite films: toward effective electromagnetic shielding

Abstract

Cross and secondary electromagnetic pollution is a major challenge in current electromagnetic interference (EMI) mitigation. In this study, Fe₃O₄@MnO₂ composite microspheres and AgNWs were prepared using modified solvothermal and hydrothermal methods. By optimizing the fabrication process and structural design of electromagnetic shielding composite films, we successfully constructed a composite film with superior shielding performance and reduced thickness. The Fe₃O₄@MnO₂ composite exhibited an SE_A/SE_T ratio of 83.32%, along with a high absorption coefficient A, indicating its dominant role in electromagnetic wave absorption, thereby mitigating excessive reflection. Results demonstrated that the gradient network-structured film possessed significantly enhanced electromagnetic wave absorption and attenuation capabilities compared to other three composite materials. The SE_A/SE_T of the gradient network-structured film reached 86%, with a maximum SE_T of 58.65 dB. This hierarchical structure not only improves shielding effectiveness at reduced thickness but also enhances absorption, achieving the ultimate goal of high absorption with low reflection while minimizing resource consumption.