Hollow Beaded Fe₃C/N-Doped Carbon Fibers toward Broadband Microwave Absorption

Microwave-absorbing materials have attracted enormous attention for electromagnetic (EM) pollution. Herein, hollow beaded Fe₃C/N-doped carbon fibers (Fe₃C/NCFs) were synthesized through convenient electrospinning and subsequent thermal treatment. The special hollow morphology of the samples is conducive to achieve lightweight and broadband microwave absorption properties. The thermal treatment temperatures exhibit a significant impact on conductivity and EM properties. The broadest effective absorption bandwidth (EAB) is 5.28 GHz at 2.16 mm when the thermal treatment temperature is 700 °C, and the EAB can cover 13.13 GHz with a tunable absorber thickness from 1.0 to 3.5 mm when the thermal treatment temperature is 750 °C. The excellent microwave absorption properties of the samples are due to the synergistic effect of impedance matching and strong EM energy attenuation abilities. Hence, the magnetic hollow beaded Fe₃C/NCFs are expected to be an attractive candidate material as a lightweight and efficient microwave absorber in the future.