Core-shell Fe3Al@polypyrrole composites with tunable shell thickness and enhanced microwave absorption performance

Nowadays, core-shell structures have attracted considerable attention as microwave absorbers (MAs) due to the synergistic effect between dielectric and magnetic loss. Herein, core-shell Fe3Al@polypyrrole (Fe3Al@PPy) composites were successfully fabricated by the thermit reaction and chemical oxidation polymerization method with the assistance of ammonium persulfate and p-toluene sulfonic acid. Due to the regulation of the impedance matching by the electromagnetic coupling and core-shell structure, the Fe3Al@PPy composites showed enhanced electromagnetic wave (EMW) absorption performance compared with the pure Fe3Al. Furthermore, the thickness of the PPy shell increased from 0.23 μm to 1.50 μm as the addition of pyrrole (Py) increased from 0.25 mL to 1.0 mL. Meanwhile, the core-shell Fe3Al@PPy composites exhibited the optimal wave absorption performance when the PPy shell thickness was 0.80 μm, and the reflection loss (RL) could reach -40.53 dB with the thickness of 2.0 mm at 13.3 GHz. This work provides a new idea for the design of large-scale electromagnetic (EM) coupled MAs with core-shell structures.