Light-weight 1D heteroatoms-doped Fe3C@C nanofibers for microwave absorption with a thinner matching thickness

Highlights: • The 1D heteroatoms-doped Fe₃C@C absorber is prepared using a facile method. • Chemical states of nitrogen atoms are influenced by thermal treatment process. • The maximum EAB reaches 4.9 GHz with the thickness of 1.6 mm. • Excellent MA ability is achieved due to synergistic effect of multiple mechanisms. -- Abstract: Emergency situation of electromagnetic microwave pollution generated by daily electronic devices urgently requires light-weight and efficient microwave absorption materials with thin thickness and low filling ratio. Herein, the heteroatoms-doped Fe₃C@C nanofibers are fabricated from a mixture solution of Iron (III) 2, 4-pentanedionate (Fe(acac)₃) and nitrogen-containing polymer poly (phthalazinone ether nitrile ketone) (PPENK) by electrospinning and the following thermal treatment. The morphologies and compositions of nanofibers can be controlled by annealing temperature. The 1-Dimensional (1D) heteroatoms-doped Fe₃C@C nanofibers display outstanding microwave absorption performance. When the filling ratio is 30 wt% in paraffin for nanofibers heat-treated in 700 ℃, the optimal reflection loss value is − 35.5 dB at 8.3 GHz with a thickness of 2.8 mm. Additionally, the maximal efficient absorption bandwidth reaches as wide as 4.9 GHz ranging from 13.1 to 18.0 GHz with a rather thin thickness of 1.6 mm. The Fe₃C@C nanofibers have adjustable electromagnetic parameters and thus, balance impedance matching and microwave attenuation performance at the same time. This work investigates the relationship between microwave absorption performance and the chemical states of nitrogen atoms, revealing a facile strategy to prepare a multi-interface microwave absorber and presenting a candidate application for microwave absorption materials with low matching thickness.