Self-Assembled Co Nanosheet/Ti₃C₂T_x Composites with Tunable Electromagnetic Wave Absorption

Abstract

Two-dimensional layered Ti 3 C 2 T x is a great potential candidate as an electromagnetic wave (EMW) absorber due to its large specific surface area and abundant functional groups and defects. However, the impedance mismatch caused by the high conductivity and the lack of magnetic loss seriously has limited the application of Ti 3 C 2 T x in EMW absorption. Therefore, Co/ Ti 3 C 2 T x composites were prepared by combining Ti 3 C 2 T x with magnetic Co nanosheets through electrostatic self-assembly. It is found that desired EMW absorption performance could be obtained by optimizing the content of Co nanosheet. Specifically, the optimized sample exhibited a minimum reflection loss (RL min ) value of −47.09 dB and an effective absorption bandwidth of 2.76 GHz as the thickness was 3.67 mm. In addition, possible mechanisms of EMW absorption were elucidated in detail. Our results provide a simple and environmentally friendly method for the design of EMW absorbers based on Ti 3 C 2 T x .

Boron Nitride- and Carbon Nanotube-Bridged Interfaces for Boosting Thermal Conduction and Electromagnetic Wave Absorption

“…Generally, the value of RL below −10 dB indicates that the absorber can absorb 90% of EWs. 45 Figure 5 shows the RL value of four BN/Ni/CNT/WPU films within 1.0−5.0 mm thickness at frequency range of 2−18 GHz. The BN 0.5 /Ni 0.5 /CNT 1 /WPU film exhibits the poorest EWA ability, with almost all of the RL min values higher than −10 dB within the thicknesses of 1.0−5.0 mm (Figure 5a−c).…”

High-Efficiency Electromagnetic Interference Shielding from Highly Aligned MXene Porous Composites via Controlled Directional Freezing

“…In addition, the formation of conductive networks inside the PCMs provides conductive paths for electron migration and leapfrogging, and thus conductive losses occur. 70 The MXene surface contains abundant functional groups (−O, −OH, −F) and local defects causing dipole polarization and interfacial polarization, and the nonhomogeneous interface between the MXene nanosheets and CNTs triggers charge accumulation, which dissipates the incident electromagnetic waves. 71−73 The above results demonstrate that the lightweight MSC PCMs exhibit excellent electromagnetic shielding performance and provide an effective strategy for the construction of 3D highperformance electromagnetic shielding materials.…”

Fabrication and Microwave Absorption Properties of FeSiAl@PANI Composites

“…The presence of multiple twisted Cole–Cole semicircles on the Debye relaxation curves can be seen in Figure a–d, indicating the presence of other polarization mechanisms such as conductivity loss, interfacial polarization, oxygen defects, etc. , Where the two Cole–Cole semicircles of Figure a correspond to the two relaxation peaks at 2.44 and 14.68 GHz for the ε″ of the S 0 sample. The FeSiAl surface is coated with massive PANI, resulting in abundant nonhomogeneous interfaces, and under the action of alternating electromagnetic field, the charge aggregates on the nonhomogeneous interfaces to produce interfacial polarization. − Besides the interfacial polarization, the FeSiAl@PANI composites introduced a large number of defects during the preparation process, and these defects and the functional groups of PANI can act as a dipole, whose directional rotation induces a dipole polarization. , Thus, the relative concentration of the two semicircles indicates the dipole polarization and interfacial polarization produced by the PANI cladding (Figure b). Moreover, as shown in Figure b–d, there is a long smooth tail appearing in the Cole–Cole plots of S 1 , S 2 , and S 3 samples.…”