Traditional single-component microwave absorbers face the difficulties including the narrow absorption bandwidth and low absorption strength. Herein, we develop a novel dual-magnetic composite decorating with covalent-organic framework (COF of 1,3,5-triformylphloroglucinol and p-phenylenediamine: TpPa) and carbon hybrid to enhance microwave absorption performance. Namely, a dual-magnetic FeSiAl@(CoFeO/C)@TpPa core–shell structure with rich interfacial polarizations was prepared by the three main steps: firstly, the plate-like FeSiAl was decorated with the MOFs of ZIF-67. And then it was converted to FeSiAl@(CoFeO/C) after an annealing process under Ar. Lastly, the growth of COF (TpPa) was designed for enhanced microwave penetration into the interior of absorbers. The as-design dual-magnetic FeSiAl/CoFeO effectively favors to magnetic domain resonance resulting in the dual-magnetic coupling effects. Meanwhile, the multi-level structure formed by ultra-fine carbon in FeSiAl@(CoFeO/C)@TpPa enables magnetic-dielectric synergies and enriches the attenuation path as well. Furthermore, the accumulation of transferred charge at multiple interfaces provides a stronger relaxation polarization loss. The above positive factors collectively promote the high-performance microwave absorption with the reflection loss (RL) value up to −51.3 dB and the effective absorption bandwidth (EAB) covers 3.2–17.7 GHz by adjusting the thickness of absorbers. Therefore, this dual-magnetic/dielectric coupling approach provides an innovative strategy for fabricating advanced microwave absorbers.

中文翻译：

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MOF/COF 衍生物装饰 FeSiAl 耦合磁和电损耗以增强微波吸收

传统的单组分微波吸收体面临着吸收带宽窄、吸收强度低等难题。在此，我们开发了一种新型双磁性复合材料，具有共价有机骨架（1,3,5-三甲酰基间苯三酚和对苯二胺的COF：TpPa）和碳杂化物，以增强微波吸收性能。即，通过三个主要步骤制备了具有丰富界面极化的双磁性FeSiAl@(CoFeO/C)@TpPa核壳结构：首先，用ZIF-67的MOFs装饰片状FeSiAl。然后在Ar气氛下进行退火处理后转化为FeSiAl@(CoFeO/C)。最后，COF (TpPa) 的增长旨在增强微波对吸收体内部的渗透。设计的双磁 FeSiAl/CoFeO 有效地有利于磁域共振，从而产生双磁耦合效应。同时，FeSiAl@(CoFeO/C)@TpPa中超细碳形成的多级结构能够实现磁介电协同作用，也丰富了衰减路径。此外，转移电荷在多个界面处的积累提供了更强的弛豫极化损耗。上述积极因素共同促进了高性能微波吸收，通过调整吸收体的厚度，反射损耗（RL）值高达-51.3 dB，有效吸收带宽（EAB）覆盖3.2-17.7 GHz。因此，这种双磁/介电耦合方法为制造先进的微波吸收器提供了一种创新策略。