Nanoconfinement strategy for lightweight FeCoNi/N-doped carbon nanotubes with broadband electromagnetic absorption

Designing rational and lightweight magnetic-dielectric composites for efficient electromagnetic wave absorption remains a significant challenge. Herein, the FeCoNi metal-induced nitrogen-doped carbon nanotubes (FeCoNi@NCNTs) were synthesized though unique nanoconfinement strategy during carbon thermal reduction reaction. In confined environment, sufficient conditions were provided for the multidimensional growth of nanostructures. The mechanisms of carbon nanotube growth and electromagnetic wave absorption were further investigated. The FeCoNi@NCNTs exhibited a minimum reflection loss of -59.5 dB within the 2–18 GHz frequency range. Moreover, the composite achieved a minimum effective absorption bandwidth of 5.3 GHz at 2.0 mm. This work provides a new insight for preparing various magnetic-dielectric composites with rich absorption effects and broadband microwave absorption.