Construction of nitrogen-doped graphene-based ternary magnetic composite aerogel towards excellent electromagnetic absorption in the Ku-band

The development of advanced electromagnetic wave (EMW) absorbing materials with broad bandwidth, strong absorption, low filler loading ratio and small thickness remains a great challenge. In this work, nitrogen-doped reduced graphene oxide/multi-walled carbon nanotubes/hollow nickel ferrite (NRGO/MWCNTs/hollow NiFe2O4) ternary magnetic composite aerogel with the ultralow bulk density was synthesized via the two-step route of solvothermal synthesis and hydrothermal self-assembly. Results of microscopic morphology characterization showed that as-synthesized binary and ternary magnetic composite aerogels exhibited the special three-dimensional hierarchical porous network structure. Moreover, the EMW absorption performance of ternary composite aerogel was obviously enhanced in comparison with NRGO/MWCNTs and NRGO/hollow NiFe2O4 binary composite aerogels. Remarkably, the attained NRGO/MWCNTs/hollow NiFe2O4 ternary composite aerogel showed the maximum absorption bandwidth of 6.7 GHz (11.3-18.0 GHz) and robust absorbing intensity of - 42.8 dB at a thin matching thickness of 2.0 mm and a low loading ratio of 12.5 wt%. It was worth noting that when the matching thickness was slightly increased to 2.1 mm, the optimal minimum reflection loss could reach - 69.0 dB. The special hierarchical porous network structure and magnetodielectric synergy in the ternary composite aerogel optimized the impedance matching, and notably enhanced the EMW absorbing capacity. Therefore, this work could contribute to the construction of graphene-based hybrid nanocomposites as advanced EMW absorbers. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In this study, a nitrogen-doped reduced graphene oxide/multi-walled carbon nanotubes/hollow nickel ferrite ternary magnetic composite aerogel with ultralow bulk density was successfully synthesized. The synthesized binary and ternary magnetic composite aerogels exhibited a unique three-dimensional hierarchical porous network structure. The ternary composite aerogel showed significantly enhanced electromagnetic wave absorption performance compared to the binary composite aerogels. Remarkably, the ternary composite aerogel achieved a maximum absorption bandwidth of 6.7 GHz and a robust absorbing intensity of -42.8 dB at a thin matching thickness of 2.0 mm and a low loading ratio of 12.5 wt%. The impedance matching was optimized by the special hierarchical porous network structure and magnetodielectric synergy, resulting in the notable enhancement of the electromagnetic wave absorbing capacity. Therefore, this work is of great importance for the development of graphene-based hybrid nanocomposites as advanced electromagnetic wave absorbers.