A seed germination-inspired interface polarization augmentation strategy toward superior electromagnetic absorption performance

Abstract

Dielectric/magnetic composites are considered as attractive candidates for high-performance electromagnetic wave absorption (EMA) materials. However, the agglomeration of magnetic nanoparticles (NPs) in the carbon matrix is an unavoidable problem. The homogeneous interfaces caused by magnetic agglomeration are often detrimental to the reinforcement of interfacial polarization. Herein, inspired by seed germination process, a high temperature derived carbon nanotube method was employed to prevent the agglomeration issue of magnetic NiCo alloy NPs. With the significant proliferation of heterogeneous interfaces due to the separation between NiCo alloy NPs, the interfacial polarization is significantly reinforced. Besides, the graphitized carbon obtained by high temperature carbonization is responsible for the conductive loss. As a consequence, the NiCo alloy@N doping carbon nanosheets (NiCo@NCS) composites illustrated a strong EM attenuation ability compared to the composites with magnetic NiCo alloy NPs agglomeration. Finally, the minimum reflection loss (RLmin) was −61.4 dB and widest absorption bandwidth (fmax) reached 4.72 GHz at 2.0 mm and 2.1 mm, respectively. This seed germination-inspired approach can be a significant and efficient reference to prevent the agglomeration of magnetic NPs in dielectric/magnetic composites.