Magnetic carbon-based aerogels with low-density and strong attenuation, have attracted significant attention as microwave absorbing materials, but still face huge challenges. Herein, magnetic FeMnC modified carbon/Graphene aerogels (NCMF) were synthesized utilizing freeze casting following a carbothermal reduction process. The conductivity, defects density, material component and electromagnetic properties can be regulated by the temperature. The NCMF aerogels exhibit remarkable microwave absorption properties, with an effective absorption bandwidth of 5.76 GHz at a thickness of 2.1 mm and a minimum reflection loss as low as −50.8 dB at 7.52 GHz with a fill ratio of only 5 wt%. The exceptional microwave absorption capabilities of NCMF aerogels are attributed to the synergistic effects of dielectric loss, magnetic loss, three-dimensional (3D) carbon conductive network, and the optimal impedance matching. Consequently, this research paves a way for the development of microwave absorbing materials with lightweight, broadband and strong microwave absorption at low loading.

中文翻译：

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用于宽带微波吸收的多界面磁性FeMnC改性碳/石墨烯气凝胶的构建


磁性碳基气凝胶具有低密度、强衰减的特点，作为微波吸收材料引起了人们的广泛关注，但仍面临巨大的挑战。在此，磁性 FeMnC 改性碳/石墨烯气凝胶（NCMF）是在碳热还原过程后利用冷冻铸造合成的。电导率、缺陷密度、材料成分和电磁特性可以通过温度调节。 NCMF气凝胶表现出卓越的微波吸收性能，在2.1mm厚度下有效吸收带宽为5.76GHz，在7.52GHz下最小反射损耗低至-50.8dB，填充率仅为5wt%。 NCMF气凝胶优异的微波吸收能力归因于介电损耗、磁损耗、三维（3D）碳导电网络和最佳阻抗匹配的协同效应。因此，这项研究为开发轻质、宽带、低负载下强微波吸收的微波吸收材料铺平了道路。