ZnFe2O4@SiO2/C Composites Synthesized by High-Temperature Mechanochemical Technology for Efficient Electromagnetic Wave Absorption in the X-Band

Constructing a reasonable dielectric-magnetic synergistic effect is an effective way to prepare high-performance electromagnetic wave absorbers. In this paper, ZnFe2O4@SiO2/C composites with a close-packed structure were successfully synthesized by an efficient condensation reaction of a silane coupling agent and high-temperature mechanochemical technology. The silane coupling agent can effectively adjust the occurrence state of ZnFe2O4 and the graphite interlayer compound, so as to realize the adjustable electromagnetic parameters. When the ratio of silane coupling agent, deionized water, and anhydrous ethanol is 1:1:1, ZnFe2O4@SiO2/C composites achieve a minimum reflection loss value (RLmin) of −52.5 dB at a thickness of 1.87 mm and a maximum effective absorption bandwidth (EABmax) of 4.16 GHz at a thickness of 2.07 mm. In addition, the EAB covers 8–12 GHz at a thickness of 1.97 mm, achieving efficient absorption of X-band electromagnetic waves. Through the optimization of structure and composition, the problems of large thickness and limited electromagnetic wave performance of ZnFe2O4/C composites are effectively improved, which provides a way for the design and large-scale preparation of ZnFe2O4-based absorbers with high electromagnetic wave absorption performance in the X-band.