Hollow porous CoNi/C composite nanomaterials derived from MOFs for efficient and lightweight electromagnetic wave absorber

Hierarchical composite of biomass derived magnetic carbon framework and phytic acid doped polyanilne with prominent electromagnetic wave absorption capacity

The appearance and development of two-dimensional titanium carbide materials provide a new idea for our research on microwave absorption materials. Its excellent electrical conductivity and surface functional groups allow it to be used as a microwave absorber. In this study, Ti3C2Tx@NiCo2O4 composites were prepared by simple hydrothermal method and subsequent annealing process. With the change of annealing temperature, the state of composites is changed, so the structure and properties of samples are further adjusted. When the annealing temperature is 350 °C, an optimal reflection loss value of −50.96 dB can be obtained at 2.18 mm. The excellent microwave absorption performance is not only caused by polarization behavior, but also related to multiple reflections and multiple scattering produced by unique structures. Therefore, the prepared Ti3C2Tx@NiCo2O4 is expected to be a promising microwave absorber with thin thickness and high absorption intensity.

Preparation of two-dimensional titanium carbide (Ti3C2Tx) and NiCo2O4 composites to achieve excellent microwave absorption properties

Developing electromagnetic absorption materials with a strong absorption ability and wide absorption bandwidth has attracted widespread attention in the field of electromagnetic shielding, but it still remains a great challenge. Herein, we successfully developed 2D hierarchically laminated Fe3O4@nanoporous carbon (NPC)@rGO magnetic/dielectric nanocomposites as high-performance microwave absorbers through a facile microwave-assisted approach. The rational design of the composition (Fe3O4, NPC and rGO) and the hierarchical microstructure provided the nanocomposite with a micro-scale 3D magnetic coupling network, a hierarchical dielectric carbon network and good impedance matching, which were identified by the off-axis electronic holography and electromagnetic characterization. As expected, the Fe3O4@NPC@rGO composites achieved a strong reflection loss of −72.6 dB, a matching thickness of 2.0 mm and a broad bandwidth of 5.5 GHz. Such excellent achievements encourage the development of hierarchical magnetic EMA absorbers and provide remarkable inspiration for designing high-performance microwave absorbers.

https://pubs.rsc.org/en/content/articlepdf/2020/tc/c9tc06526a

Rational design of 2D hierarchically laminated Fe3O4@nanoporous carbon@rGO nanocomposites with strong magnetic coupling for excellent electromagnetic absorption applications

Hierarchical Fe3O4/Fe@C@MoS2 core-shell nanofibers for efficient microwave absorption

Fabricating of bio-derived electromagnetic wave absorbing materials has become hotspot. However, many bio-derived absorbers still suffer from thicker matching thickness limiting their application. Herein, porous carbon foams derived from fish skin have been synthesized through a simple hydrothermal method for the first time. Then Fe3O4 nanospheres with diameter of 30 nm were uniformly imbedded into the carbon matrix via refluxing and annealing treatment. By controlling the precursor ratio of Fe(NO3)3·9H2O and carbon, optimized microstructure and component can be easily realized. As expected, the novel Fe3O4/C foams show outstanding electromagnetic wave absorption performance compared with single carbon foams. When the loading filler ratio was 25 wt%, the minimum RL value of FC-3 can reach −47.3 dB with a small matching thickness of 1.9 mm. Moreover, the effective absorption bandwidth was 5.68 GHz (12.16–17.84 GHz) with the thickness of 2.2 mm. The thin matching thickness could ascribe to the addition of Fe3O4 nanospheres which could introduce more dielectric loss and magnetic loss. Moreover, the matching thickness of FC-3 is much thinner than other reported bio-derived materials. This investigation could be a perspective paving for the fabrication and mechanism research of electromagnetic wave absorber derived from animal organs.

Shaolei Qu

Papers

Synthesis of Fe3O4/carbon foams composites with broadened bandwidth and excellent electromagnetic wave absorption performance

Synthesis of porous carbon embedded with NiCo/CoNiO2 hybrids composites for excellent electromagnetic wave absorption performance.