Magnetic Ni/graphene connected with conductive carbon nano-onions or nanotubes by atomic layer deposition for lightweight and low-frequency microwave absorption

By Xuefei Xu, Guizhen Wang, G. Wan, Shaohua Shi, C. Hao, Yu Tang, Guilong Wang. 2020

239 citations recorded by the source corpus.

Abstract Microwave absorbing materials (MAMs) have been researched in depth due to the increasing electromagnetic (EA) pollution produced by rapid-developed electronic technologies. Lightweight and high-conductivity graphene-based MAMs are quite promising, but there also exists a big challenge for them to achieve satisfactory low-frequency microwave absorption performance with a low filler loading ratio. Here, two novel hierarchical structures, Ni@carbon nano-onions and Ni/carbon nanotubes adhering on graphene surfaces (Ni@C/G and Ni/CNT/G) were designed and synthesized by precisely controlling the size and content of NiO with an atomic layer deposition-assisted method. Such innovative constructions can endow them a variety of advantages for microwave absorption including multiple interfaces, micro-current networks and good impedance matching, which ensures them to be high-efficiency and low-frequency microwave absorbers with low densities. Optimized NCG 100 exhibits excellent microwave absorption performance in C band with the minimum RL value reaching −45.5 dB at 6.2 GHz, and the widest absorption band was measured to be 5.6 GHz at the thickness of 2.5 mm. In addition, compared to most of graphene- and Ni-based absorbers, Ni@C/G and Ni/CNT/G achieve higher performance by utilizing a lower filler loading ratio of only 15%. Our findings may pave the way for designing lightweight low-frequency MAMs.

Subfields: Aerospace Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/c9d0f9a79fb2a510582625b739db786864e17985