Facile fabrication of NiFe2O4-FeNi/C heterointerface composites with balanced magnetic-dielectric loss for boosting electromagnetic wave absorption

Abstract

In the electronic information age, and even in the impending “intelligent era”, electromagnetic wave (EMW) absorbers have inevitably received more and more attention. However, their practical applications are currently limited by a lack of suitable mass-production strategies for high performance EMW absorbers. Herein, we propose a facile strategy for large-scale and controllable preparation of NiFe2O4-FeNi/C (NFO-FN/C) composites with various microstructural features advantageous to enhanced EMW absorption, including core-shell structure, porous structure, hierarchical nano-micro topography, and electromagnetic heterointerfaces. The composites are synthesized through the confinement pyrolysis of the polydopamine (PDA)-coated NiFe2O4 (NFO), and their microstructural features can be facilely tailored by changing the number of PDA confinement. The synthesized composite of NFO-FN/C-2 performs best after two repetitions of PDA confinement throughout the preparation process, with a reflection loss (RLmin) of −68.74 dB at a thickness of 1.61 mm and a broad effective absorption of 6.37 GHz at a thickness of 1.9 mm. This impressive EMW absorption performance is attributed to the synergistic effect of multiple loss mechanisms and excellent impedance matching derived from the tailored microstructural features of our EMW absorbers. This work provides a new perspective on the large-scale preparation of highly efficient EMW absorbing materials.