Electromagnetic (EM) functional materials play an increasingly important role in solving EM wave pollution in both modern military and civil fields. Graphene‐based materials are the most promising candidates in the applications of EM wave shielding and absorption owing to their remarkable structures and enhanced EM properties. Designing graphene‐based materials with elaborately controlled microstructures and optimized EM properties can effectively improve EM energy attenuation and conversion. Herein, the study begins with the EM attenuation mechanism, and multiscale design strategies of graphene‐based EM functional materials are outlined, including molecular‐scale, micro/nanoscale structure, macroscale structure, and integration of multiscale assembly design strategies. Applications in the EM wave shielding and absorption fields are reviewed, focusing on the latest advances in graphene‐based assemblies such as films, fabrics, and composites. Finally, the current challenges and future directions in this fast‐growing field are predicted.

A Review on Graphene‐Based Electromagnetic Functional Materials: Electromagnetic Wave Shielding and Absorption

• CB/Co@C nanocomposites composed of sustainable carbon black and anchored Co@C nanoparticles have been successfully synthesized. • As a novel lightweight electromagnetic wave absorber, the optimal RL min and EAB of -53.989 dB and 6.0 GHz were achieved at thin thickness. • A reasonable absorption mechanism was proposed according to various loss mechanism induced by different components. Recently, developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic wave absorbers. In the current work, reclaimed carbon black (CB) nanopowder was firstly produced by simple burning of wheat straw, which was then employed as sustainable carbon-based host materials (carrier) and successfully decorated Co@C nanoparticles via a simple thermal reduction process. Remarkably, both the as-fabricated nanocomposites and corresponding electromagnetic wave absorption performances could be effectively tuned by tailoring the dosage of the Co@C nanoparticles. The minimum reflection loss (RL min ) of –53.989 dB was achieved for CB/Co@C-2# at 2.28 mm thickness, meanwhile, CB/Co@C-3# was featured by a wide effective absorption band (EAB) of 6 GHz (6.72–12.72 GHz) at a 2.73 mm matching thickness, which covered the entire X band, suggesting that the CB/Co@C nanocomposites were an attractive candidate for electromagnetic wave absorber. According to the synergistic influence of dielectric loss and magnetic loss from CB and Co@C, respectively, as well as the properly matched impedance, a reasonable electromagnetic wave attenuation mechanism was illustrated. It is noteworthy that the preparation process of CB is a facile, recycled, and low-cost strategy for achieving nanoscale carbon-based absorbing materials, moreover, the CB/Co@C nanocomposites provide a reference for constructing lightweight dielectric-magnetic products with superb electromagnetic wave absorption performances. 

Monodispersed Co@C nanoparticles anchored on reclaimed carbon black toward high-performance electromagnetic wave absorption

Cu/NC@Co/NC composites derived from core-shell Cu-MOF@Co-MOF and their electromagnetic wave absorption properties

Fabrication of bimetallic metal-organic frameworks derived cobalt iron alloy@carbon-carbon nanotubes composites as ultrathin and high-efficiency microwave absorbers.

Synthesis of FeCoNi/C decorated graphene composites derived from trimetallic metal-organic framework as ultrathin and high-performance electromagnetic wave absorbers.

Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe3O4/C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe3+ to Zn2+ in the precursors. Moreover, results revealed that the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe3+ to Zn2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs.

Jianjun Shi

Papers

Fabrication of bimetallic metal-organic frameworks derived Fe3O4/C decorated graphene composites as high-efficiency and broadband microwave absorbers