Difunctional (heterogeneous doping of BN)@Fe3O4@Ppy composite for excellent microwave absorption performance in mid-to-low frequency range and high-efficient thermal management

Abstract

As AI technology advances rapidly, addressing mid to low-frequency electromagnetic wave pollution and thermal management in precision electronic devices is essential. Integrating microwave absorption and thermal management into dual-functional composites is a promising solution to these challenges. Herein, BCNO@Fe₃O₄@Ppy (BFePP) absorbers possessing a core-shell structure were successfully fabricated by depositing Fe₃O₄ and polypyrrole (Ppy) covering the surface of previously prepared C, O hetero element doped h-BN (BCNO) by hydrothermal and in situ growth techniques. The BFePP three-component system facilitates the multi-wall reflection and scattering of electromagnetic waves, significantly enhancing its electromagnetic wave attenuation performance. The electrical conductivity can be precisely tuned by adjusting the Ppy content, thereby optimizing impedance matching with free space and improving wave attenuation efficiency. Notably, BFePP-2 exhibited a minimum reflection loss (RLmin) of −52.58 dB at 4 GHz and an effective absorption bandwidth (EAB) of 4.3 GHz, underscoring its remarkable capacity for efficiently absorbing low- and medium-frequency electromagnetic waves. In addition, the effective wave-absorbing range of BFePP-2 spans nearly the entire test spectrum. The precise structural design allows Fe₃O₄ and Ppy to grow orderly on the BCNO surface, significantly reducing interfacial thermal resistance and phonon scattering, thus enhancing heat transfer efficiency. Furthermore, the presence of Ppy on the surface of the composite facilitates the dispersion of the composite within the EP, leading to a reduction in interfacial thermal resistance. This improved dispersion boosts heat conduction across the system. Consequently, the thermal conductivity of BFePP-2/EP reaches 1.8 W(m·K)⁻¹, a 611.46 % increase compared to pure EP. This study introduces an innovative approach for optimizing microwave absorbers, holding significant promise for future research and technological advancements in this area.