Magnetic crystallite-decorated hollow multi-cavity carbon nanosheet spheres for superior electromagnetic absorption. (5th March 2023)

• Record Type: Journal Article
• Authors: Liu, Zhuoyue; Tian, Honglin; Xu, Renxin; Men, Weiwei; Su, Tao; Qu, Yangguang; Zhao, Wei; Liu, Dan
• Is Part Of: Carbon. Volume 205(2023)
• Page Start: 138
• Page End: 150
• Publication Date: 2023-03-05
• Subjects: Hierarchically porous structure -- Carbon nanosheets -- Magnetic crystallite -- Microwave absorption; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2023.01.031
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Carbonaceous-magnetic composites have emerged as the most attractive absorbers in recent years, and creating hierarchically porous structures in composites is generally considered an indispensable strategy to enhance overall performance. Herein, we design a series of carbonaceous-magnetic composites with superior electromagnetic absorption performance. Via simple spray-drying of a solution containing metal/carbon precursors and a water-removal salt template (i.e., NaCl), the as-made materials feature a complex hierarchical architecture with a hollow interior and a multi-cavity shell, which is assembled from ultrathin carbon nanosheets decorated with magnetic crystallites. The proposed method is generally applicable and can integrate various magnetic crystallites (e.g., Fe3 O4, Ni, FeCo, and CoFe2 O4 ) into hollow multi-cavity carbon spheres. The optimal Fe3 O4 -based absorber achieves effective absorption bandwidth (7.7–13.4 GHz) covering the entire X band and excellent electromagnetic attenuation capability (−51.1 dB) with a thin thickness of 2.7 mm. Furthermore, a simulation demonstrates that an absorbing coating with the optimal absorber enables remarkably reduced radar cross section lower than −10 dBm 2 over the whole measurement range. These results indicate that proposed microwave absorbing materials have practical feasibility in civilian and military stealth applications. Graphical abstract: Image 1 Highlights: A scalable spray-drying method is used to prepare microwave absorbers with a hollow interior and a multi-cavity shell. The proposed method can integrate various magnetic crystallites into hollow multi-cavity carbon spheres. The optimal material achieves a strong reflection loss (−51.1 dB) and a broad effective absorption bandwidth (5.7 GHz). A simulation demonstrates that an absorbing coating with the absorber enables remarkably reduced radar cross section.