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

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.

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

Preparation of FeNi/C composite derived from metal-organic frameworks as high-efficiency microwave absorbers at ultrathin thickness.

Hierarchical carbon nanotubes@Ni/C foams for high-performance microwave absorption

• Ultralight magnetic composite foam with hierarchical structure is fabricated. • Loading of MXene/FeS on rGO promotes the formation of hierarchical impedance in foam. • Hierarchical impedance structure facilitates the entrance and dissipation of EMW. • Optimization of impedance structure improves absorption capacity and bandwidth. Developing high-performance broadband microwave absorption material becomes an urgent concern in the field of electromagnetic protection. In this work, an ultralight magnetic composite foam was constructed by electrostatic self-assembly of MXene on the surface of graphene skeletons, and subsequent hydrothermal anchoring of flower-shaped FeS clusters. Under the synergistic effect of MXene coating increasing conductive loss and FeS clusters improving magnetic loss, the rational construction of hierarchical impedance structure in foam can effectively promote the entrance and consumption of more incident electromagnetic waves. The minimum reflection loss (RL min ) reaches –47.17 dB at a thickness of 4.78 mm, and the corresponding effective absorption bandwidth (EAB) is up to 6.15 GHz. More importantly, the microwave absorption performance of composite foam can be further optimized by controlling the loading of MXene and thermal treatment at a low temperature. The maximum of EAB for GMF-300 can be extended to an unprecedented value of 11.20 GHz (covering 6.10–17.30 GHz). 

Hierarchical graphene@MXene composite foam modified with flower-shaped FeS for efficient and broadband electromagnetic absorption

Fabrication of ultralight nitrogen-doped reduced graphene oxide/nickel ferrite composite foams with three-dimensional porous network structure as ultrathin and high-performance microwave absorbers.

Fabrication of three-dimensional nitrogen-doped reduced graphene oxide/tin oxide composite aerogels as high-performance electromagnetic wave absorbers.

Lanlan Deng

Papers

Fabrication of ultralight nitrogen-doped reduced graphene oxide/nickel ferrite composite foams with three-dimensional porous network structure as ultrathin and high-performance microwave absorbers.

Fabrication of three-dimensional nitrogen-doped reduced graphene oxide/tin oxide composite aerogels as high-performance electromagnetic wave absorbers.