Achieving Superior Electromagnetic-Absorbing Performances in the Hexagonal Flake BaFe₁₂O₁₉@PVDF Composites

Combining magnetic and dielectric materials to form a composite can significantly improve its impedance matching and electromagnetic wave absorption performance. Furthermore, composite materials with a core-shell structure hold promise in meeting the demand for lightweight and highly electromagnetic-absorbing properties. In this study, uniform hexagonal flake barium ferrite (BaFe₁₂O₁₉) was prepared using the hydrothermal method. Subsequently, BaFe₁₂O₁₉@PVDF composites were synthesized by the sol-gel method. By adjusting the mass ratio of BaFe₁₂O₁₉ and PVDF, the shell size of the BaFe₁₂O₁₉@PVDF composite material was controlled, and its electromagnetic absorption performance was enhanced. The shell thickness of BaFe₁₂O₁₉@PVDF is 19.64 nm when the BaFe₁₂O₁₉: PVDF mass ratio is 1:1.0, and the optimal impedance matching is obtained at 13.4 GHz. Meanwhile, at a thickness of 1.5 mm, the minimum reflection loss (RL_min) reached -58.04 dB, and an effective absorption bandwidth (EAB) (RL ≤ -10 dB) of 5.53 GHz was achieved within the frequency range of 11.65 to 15.63 GHz and from 16.36 to 17.91 GHz. Besides, the composites with a matching thickness of 3.5 mm show a maximum EAB of 15.90 GHz when the mass ratio of BaFe₁₂O₁₉ to PVDF is 1:1.2. Within the frequency range of 2-18 GHz, the coverage of reflection loss less than -10 dB is 99.38%, almost achieving full coverage. These results demonstrate that BaFe₁₂O₁₉@PVDF composites exhibit excellent electromagnetic-absorbing performances, making them an excellent candidate for electromagnetic wave absorption in 5G communications.