Layered 3D structure derived from MXene/magnetic carbon nanotubes for ultra-broadband electromagnetic wave absorption

Magnetic manganese-based composites with multiple loss mechanisms towards broadband absorption

Multiple relaxation behaviors are promising for broad frequency band and strong electromagnetic wave (EMW) absorption based on polarization‐controlled electromagnetic (EM) attenuation. However, rational selection of materials and structure manipulation through tunable substitution or phase control are challenging toward optimization of EMW absorption. Herein, bi‐metallic organic frameworks (B‐MOFs) with various morphologies are employed as EMW absorbers. Remarkably, the polar units can be enhanced by introducing Ni‐metal nodes into the Cu‐coordinated MOFs, rendering the B‐MOFs with self‐polarized properties and consecutive multifrequency EMW absorption behaviors. The maximum reflection loss of acetylene black (ACET) filled NiCu‐MOFs can reach –40.54 dB together with a wide bandwidth (<‐10 dB) of 5.87 GHz at a thickness of 2.5 mm. As a counterpart of the Ni/Cu/C derivatives, significantly increased broad band absorption (6.93 GHz) and multifrequency absorbing and polarization characteristics are also maintained in bimetal coexisting carbonized architectures as prepared by calcination of CuNi‐MOFs. This work demonstrates that the performance of effective absorbing frequency band can be enhanced in multi‐metallic organic frameworks‐based architectures, and paves a novel avenue for developing broadband and strong EMW absorbers.

Tailoring Self‐Polarization of Bimetallic Organic Frameworks with Multiple Polar Units Toward High‐Performance Consecutive Multi‐Band Electromagnetic Wave Absorption at Gigahertz

Synergistic construction of three-dimensional conductive network and double heterointerface polarization via magnetic FeNi for broadband microwave absorption

For the purpose of achieving excellent electromagnetic wave absorption performance, composition control and microstructure design of absorbers are crucial. Ti3C2Tx, transition metal carbides with remarkable conductivity and mechanical properties, are considered as common substrates to construct high-performance absorbers. In order to improve the impedance matching and enrich electromagnetic wave attenuation mechanism of single Ti3C2Tx substrate, transition metal sulfides (MoS2, NiS) with outstanding dielectric properties are introduced to fabricate the novel system of NiS/MoS2/Ti3C2Tx. Notably, this system has a unique multilayer-scale structure that spherical NiS particles are decorated on the multilayered Ti3C2Tx substrate and two-dimensional (2D) MoS2 nanosheets stack on the surface like scales. Under the synergistic effects of intense dielectric loss and multiple reflection, NiS/MoS2/Ti3C2Tx hybrid shows the wide effective absorption bandwidth (EAB) of 5.04 GHz at 2.1 mm and the minimum reflection loss (RLmin) of −58.48 dB at 2.4 mm. This work provides an innovative idea for the research of novel MXene-based absorbers.

Xinyu E

Papers

Synthesis of MnxOy@C hybrid composites for optimal electromagnetic wave absorption capacity and wideband absorption