Electrospinning of carbon fibers with hollow spherical cavities and embedded Ni@C nanospheres toward wideband electromagnetic wave absorption

Porous characteristics and electromagnetic (EM) synergy are two indispensable prerequisites in realizing matched impedance and superior EM wave absorption. Inspired by this thought, carbon fibers with hollow spherical cavities and embedded Ni@C nanospheres, defined as PCFs/Ni@C, are successfully fabricated by the electrospinning. Results demonstrate that the removal of SiO₂ spheres produces abundant hollow spherical cavities that can effectively adjust the dielectric constant and induce interfacial polarization, Ni-MOFs derivatives in the interior of carbon fibers strengthen magnetic loss and trigger EM synergistic effect, and the long-range conductive networks of carbon fibers provide effective electron transfer to the enhancement of conduction loss. Benefiting from the aforementioned merits, the synthesized PCFs/Ni@C composites exhibit high-efficient EM wave attenuation with wideband absorption. The maximum reflection loss is −40.4 dB and the effective absorption bandwidth reaches as high as 8.1 GHz, the specific reflection loss and specific effective absorption bandwidth are higher than that of counterparts. Furthermore, this strategy inspires us a valuable guideline for constructing EM wave absorbents with wideband absorption by manipulating porous characteristics and EM synergy.