Synthesis of sandwich microstructured expanded graphite/barium ferrite connected with carbon nanotube composite and its electromagnetic wave absorbing properties

The pursuing aim of high reflection loss and broad frequency bandwidth for electromagnetic wave (EMW) absorbing materials is a long-term task and under a close scrutiny. To construct rational microstructures for the absorber have significant impacts on increasing reflection loss and broadening frequency bandwidth. Herein, we presented a sandwich microstructured expand graphite (EG)/BaFe₁₂O₁₉ (BF) nanocomposite successfully prepared by in-situ sol-gel auto-combustion method. The experimental results showed that EG/BF nanocomposite has better EMW absorbing performance than pure EG and BF, the sandwich microstructured EG/BF connected with carbon nanotubes (CNTs) could further improve the electromagnetic performance effectively. The obtained CNT/EG/BF nanocomposite exhibited a saturation magnetization of 26.5 emu g⁻¹ at room temperature and an excellent EMW absorbing performance. The maximum reflection loss of the sandwich microstructured CNT/EG/BF composites with a thickness of 1 mm was up to −45.8 dB and the frequency bandwidth below −10 dB could reach to 4.2 GHz within the frequency range of 2–18 GHz. The research results indicated that the prepared nanocomposite showed great potential as a new type of microwave absorbing material.