Enhanced microwave absorption properties in C band of Ni/C porous nanofibers prepared by electrospinning

Ni/C porous nanofibers (NiCPNFs) have been fabricated by electrospinning and a series of subsequent heat treatment cycles. Transmission electron microscope (TEM) and brunauer-emmett-teller measurement (BET) results exhibit that NiCPNFs with a diameter of 300 nm have numerous different size pores. In the meanwhile, nickel nanoparticles (NiNPs) are evenly embedded in porous carbon nanofibers. Moreover, Raman and vibrating sample magnetometer (VSM) results indicate that NiCPNFs possess lower graphitization, lower magnetization (M_S) and higher coercivity (H_C). The electromagnetic properties of samples show that NiCPNFs have excellent microwave absorbing performance. An absorbing frequency bandwidth with reflection loss (RL) value exceeding −10 dB can reach 12.8 GHz (3.7–12.3 GHz and 13.8–18.0 GHz) when the matching thicknesses are only 2.5–5.5 mm. In addition, the more excellent effective absorbing bandwidth (RL ≤ − 20 dB) reaches 5.4 GHz in the range of 4.2–9.6 GHz. Particularly, the maximum reflection loss (RL) value can reach - 69.5 dB at 7.8 GHz with a thickness of 3.2 mm. Investigations reveal that the participation of porous carbon material in NiCPNFs could obviously improve the microwave absorbing ability of this novel composite material, especially in the C band frequency range (4–8 GHz).