Hang Tianyi, Zhou Lijie, Li Zhihui, Zheng Yifan, Yao Youqiang, Cao Yuxuan, Xu Chenhui, Jiang Shaohua, Chen Yiming, Zheng Jiajia
Key Laboratory of Urban Rail Transit Intelligent Operation and Maintenance Technology & Equipment of Zhejiang Province, College of Engineering, Zhejiang Normal University, Jinhua 321004, China.
Yongkang Hardware Technician College, Jinhua 321300, China.
Carbohydr Polym. 2024 Apr 1;329:121777. doi: 10.1016/j.carbpol.2024.121777. Epub 2024 Jan 9.
Developing high-performance microwave absorption (MA) materials becomes an urgent concern in the field of electromagnetic protection. Constructing porous framework is an efficient approach to MA owing to the abilities of adjusting impedance matching and providing more reflection and scattering paths for electromagnetic waves. Herein, a cellulose nanofibril (CNF)/honeycomb-like carbon-shell encapsulated FeCoNi@C/carbon nanotube (CNT) composite aerogel was fabricated via a facile freeze-drying method. The super-lightweight composites showed a distinctive gradient structure for reflection and scattering inside aerogel pores, micrometer small pores, and nano-fillers on the pore walls. The composite aerogel showed an ideal minimum reflection loss (RL) of -43.6 dB and remarkable adjustable effective absorption bandwidth (EAB) of 12.18 GHz due to good impedance matching, unique gradient porous structure, and synergies of multiple loss mechanisms. Therefore, this work will provide a viable strategy to improve the MA capability of absorbers by taking full advantage of constructing gradient reflection and scattering porous structure.
开发高性能微波吸收（MA）材料已成为电磁防护领域的紧迫关注点。构建多孔框架是实现微波吸收的一种有效方法，因为它能够调节阻抗匹配，并为电磁波提供更多的反射和散射路径。在此，通过一种简便的冷冻干燥方法制备了纤维素纳米纤维（CNF）/蜂窝状碳壳包覆的FeCoNi@C/碳纳米管（CNT）复合气凝胶。这种超轻复合材料在气凝胶孔内呈现出独特的用于反射和散射的梯度结构、微米级小孔以及孔壁上的纳米填料。由于良好的阻抗匹配、独特的梯度多孔结构以及多种损耗机制的协同作用，该复合气凝胶显示出-43.6 dB的理想最小反射损耗（RL）和12.18 GHz的显著可调有效吸收带宽（EAB）。因此，这项工作将提供一种可行的策略，即通过充分利用构建梯度反射和散射多孔结构来提高吸收体的微波吸收能力。
