Heterogeneous interfaces and magnetoelectric synergy in moniliform carbon nanofibers/cobalt/nitrogen-doped carbon composites for broadband and high-efficiency electromagnetic wave absorption

The rapid development of electronic information technology has brought great convenience to people's lives, but it has also caused serious electromagnetic interference and pollution problems. Therefore, it is urgent to develop broadband and highly efficient electromagnetic wave (EMW) absorbing materials. In this work, carbon nanofibers/cobalt/nitrogen-doped carbon (CNFs/Co/NC) composite fibrous materials with a unique moniliform structure were prepared for EMW absorption. By combining electrospinning with high-temperature carbonization, a three-dimensional (3D) conductive network composed of magnetic Co nanoparticles, NC and CNFs was constructed. The cross-intersections of the fibers and the abundant heterogeneous interfaces in the 3D conductive structure effectively enhanced the conduction loss and strengthened the interfacial polarization loss. Meanwhile, the uniformly anchored magnetic Co nanoparticles provided magnetic loss, which synergistically improved the impedance matching. When the calcination temperature was 700 °C and the filler loading ratio was 25 wt.%, the CNFs/Co/NC composite fiber exhibited the maximum effective absorption bandwidth of 6.8 GHz at a matching thickness of 2.95 mm and the minimum reflection loss of -52.92 dB under a thickness of 4.3 mm. Additionally, the obtained ternary composite fiber showed excellent radar cross section (RCS) reduction performance, reaching the maximum value of 32.86 dB m 2 . Therefore, this work proposes a new idea for developing CNFs-based composite materials through electrospinning as broadband and high-efficiency EMW absorbers.