Multi-shell hollow porous carbon nanoparticles with excellent microwave absorption properties

. Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

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Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption.

Electromagnetic (EM) wave absorption materials possess exceptionally high EM energy loss efficiency. With vigorous developments in nanotechnology, such materials have exhibited numerous advanced EM functions, including radiation prevention and antiradar stealth. To achieve improved EM performance and multifunctionality, the elaborate control of microstructures has become an attractive research direction. By designing them as core-shell structures with different dimensions, the combined effects, such as interfacial polarization, conduction networks, magnetic coupling, and magnetic-dielectric synergy, can significantly enhance the EM wave absorption performance. Herein, the advances in low-dimensional core-shell EM wave absorption materials are outlined and a selection of the most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship are comprehensively summarized. Moreover, the investigation of the cutting-edge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented. 

Dimensional Design and Core–Shell Engineering of Nanomaterials for Electromagnetic Wave Absorption

Lightweight Ni Foam-Based Ultra-Broadband Electromagnetic Wave Absorber

Heterostructure design of Ni/C/porous carbon nanosheet composite for enhancing the electromagnetic wave absorption

The development of lightweight and high-efficiency microwave absorption materials has attracted wide attention in the field of electromagnetic wave absorption. Herein, two kinds of petal-like Ni-based MOFs were grown on the surface of graphene nanosheets, and then pyrolyzed to obtain new microwave absorbers. The extraordinary microwave absorption performance mainly comes from: the unique petal-like porous carbon framework of MOFs, the 3D conductive network formed by the connection of GNs, the polarization process between the interfaces of multiple heterogeneous components and high impedance matching brought about by magnetic Ni nanoparticles. By adjusting the filling ratio to only 10 wt%, the optimum reflection loss of the prepared composites is up to −53.99 dB, and the effective absorption bandwidth reaches 4.39 GHz when the matching thickness is only 1.4 mm. This work provides not only a facile method for the design and fabrication of two high-efficiency microwave absorbers, but also a reference for the precise control of electromagnetic absorption properties.

Facile synthesis of 3D Ni@C nanocomposites derived from two kinds of petal-like Ni-based MOFs towards lightweight and efficient microwave absorbers

Ferrero Rocher® chocolates-like FeCo/C microspheres with adjustable electromagnetic properties for effective microwave absorption

Preparation of hollow SiC spheres with biological template and research on its wave absorption properties

Realizing ultra-wideband absorption, desirable attenuation capability at high temperature and mechanical requirements for real-life applications remains a great challenge for microwave absorbing materials. Herein, we have constructed a porous carbon fiber/polymethacrylimide (CP) structure for acquiring promising microwave absorption performance and withstanding both elevated temperature and high strength in a low density. Given the ability of porous structure to induce desirable impedance matching and multiple reflection, the absorption bandwidth of CP composite can reach ultra-wideband absorption of 14 GHz at room temperature and even cover the whole X-band at 473 K. Additionally, the presence of imide ring group in polymethacrylimide and hard bubble wall endows the composite with excellent heat and compressive behaviors. Besides, the lightweight of the CP composite with a density of only 110 mg cm-3 coupled with high compressive strength of 1.05 MPa even at 453 K also satisfies the requirements in engineering applications. Compared with soft and compressible aerogel materials, we envision that the rigid porous foam absorbing material is particularly suitable for environmental extremes. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9399338

Ruiyang Tan

Papers

Multi-shell hollow porous carbon nanoparticles with excellent microwave absorption properties

Facile synthesis of 3D Ni@C nanocomposites derived from two kinds of petal-like Ni-based MOFs towards lightweight and efficient microwave absorbers

Ferrero Rocher® chocolates-like FeCo/C microspheres with adjustable electromagnetic properties for effective microwave absorption

Preparation of hollow SiC spheres with biological template and research on its wave absorption properties

Achieving Ultra-Wideband and Elevated Temperature Electromagnetic Wave Absorption via Constructing Lightweight Porous Rigid Structure