The dielectric loss of carbon materials is closely related to the microstructure and the degree of crystallization, and the microstructure modulation of electromagnetic wave absorbing carbon materials is the key to enhancing absorption properties. In this work, a porous elastic Co@CNF-PDMS composite was prepared by freeze-drying and confined catalysis. The graphitization degree and conductivity loss of carbon nanofibers (CNFs) were regulated by heat treatment temperature and Co catalyst content. The construction of a heterointerface between Co and C enhances the interfacial polarization loss. The Co@CNF-PDMS composite with 4.5 mm achieves the minimum reflection loss (RL) of –81.0 dB at 9.9 GHz and RL no higher than –12.1 dB in the whole of the X-band. After applying a load of up to 40 % strain and 100 cycles to Co@CNF-PDMS, the dielectric properties of the composite remain stable. With the increase of compression strain, the distribution density of the absorbent increases, and the CNF sheet layer extrusion contact forms a conductive path, which leads to the conductive loss increase, finally, the absorption band moves to a high frequency. The absorption band can be bi-directionally regulated by loading and strain with good stability, which provides a new strategy for the development of intelligent electromagnetic wave absorbing materials.

中文翻译：

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钴约束催化吸收频段可切换智能电磁波吸收碳复合材料


碳材料的介电损耗与微观结构和结晶程度密切相关，电磁波吸收碳材料的微观结构调控是增强吸收性能的关键。本工作通过冷冻干燥和约束催化制备了多孔弹性Co@CNF-PDMS复合材料。碳纳米纤维（CNF）的石墨化程度和电导率损失受热处理温度和Co催化剂含量的调节。 Co和C之间异质界面的构建增强了界面极化损耗。 4.5 mm 的 Co@CNF-PDMS 复合材料在 9.9 GHz 时实现了 –81.0 dB 的最小反射损耗 (RL)，并且在整个 X 波段中 RL 不高于 –12.1 dB。在对 Co@CNF-PDMS 施加高达 40% 应变的负载和 100 次循环后，复合材料的介电性能保持稳定。随着压缩应变的增加，吸收剂的分布密度增加，CNF片层挤压接触形成导电路径，导致导电损耗增加，最终吸收带向高频移动。吸收带可通过载荷和应变双向调控，稳定性良好，为智能电磁波吸波材料的发展提供了新策略。