CNT coatings grown on the outer and inner surfaces of magnetic hollow carbon fibers with enhanced electromagnetic interference shielding performance

High-performance electromagnetic interference (EMI) shielding materials have attracted more and more attention to address the increasingly serious problem of radiation pollution. The preparation of lightweight carbon fiber-based multiple-system materials with excellent EMI shielding performance has so far proven to be elusive. Herein, hollow polyacrylonitrile (PAN)-Fe₃O₄ fibers are employed to fabricate magnetic hollow carbon fibers with carbon nanotube (CNT) coatings grown on the outer and inner surfaces via a chemical vapor deposition (CVD) process. We have achieved the fabrication of a lightweight material with excellent EMI shielding performance, which can be attributed to the synergistic effect of the CNT coating, Fe₃C (Fe₃O₄ converts to Fe₃C after the CVD process) and the one-dimensional (1D) hollow structure. The EMI shielding performance is up to 80 dB and the density of the material is only ∼1.0 g cm^-3. This material could be widely applied in wearable electronics, robot joints, precision instrument protection, and so on.