Interface evolution of a C/ZnO absorption agent annealed at elevated temperature for tunable electromagnetic properties

Abstract

Excellent electromagnetic (EM) wave absorption agents that attenuate EM waves by mechanisms based on impedance matching, conductive loss and polarization loss instead of destructive interference are urgently needed but remain challenging. Here, an EM wave absorption agent with a tailorable heterogeneous interface is designed and prepared by the in situ growth of ZnO nanoparticles on the surface of mesoporous carbon hollow microspheres (PCHMs@ZnO) via hydrothermal synthesis followed by annealing. A controlled interface evolution associated with abundant heterogeneous interfaces plays a crucial role in optimized impedance matching and enhanced interfacial polarization loss. With this method, targeted EM wave absorption agents with an excellent absorption ability that is derived mainly from polarization loss and conductive loss rather than destructive interference are successfully obtained. When the PCHMs@ZnO annealed at 700°C were combined with paraffin, the effective absorption bandwidth of the resultant composites covers the whole X band, and the mean value of reflection loss (RL) reaches −12 dB, exceeding those of other reported ZnO‐based materials. When the thickness of the composites varies from 3.3 to 4.3 mm, the value of the RL is lower than −8 dB in the whole X band. This work provides a promising model for preparing high‐performance EM wave absorption agents.

Electromagnetic wave-absorbing performance of carbons, carbides, oxides, ferrites and sulfides: review and perspective

“…Nevertheless, the introduction of dopants has been confirmed to result in enormous success. By integrating dielectric loss materials, including carbon-based materials, the synthesized composites were able to induce the changed response to the electric portion of incident EMWs [116], while the integration of magnetic ingredients, such as magnetic particles, so as to cause magnetic loss in the composites was also realized [117]. For example, Che et al synthesized carbon@ZnO composites [118] by making use of carbon cloth as a conductive network, in which different morphologies of ZnO arrays were in good contact with the carbon substrate, resulting in enhanced multiscattering, interfacial polarization, and good impedance matching (figure 11(a)).…”

Enhanced Microwave-Absorbing Property of Honeycomb Sandwich Structure with a Significant Interface Effect

“…At the same time, a frequency selective surface is designed and introduced into AHSS to achieve broadband tunable microwave absorbing properties [20]. The interface between the panel matching layer and the honeycomb produces an interface polarization effect in the alternating electromagnetic field, which is known as the Maxwell-Wagner-Sillars (MWS) effect, and can also consume microwave energy [21][22][23][24]. However, the MWS effect between the panel matching layer and honeycomb has not yet been discussed and quantified.…”

High temperature metamaterial enhanced electromagnetic absorbing coating prepared with alumina ceramic

“…In recent years, numerous materials have been used in the design, preparation and research of RACs, including metal oxides, ceramics, and carbon-based materials, such as Si3N4, SiCf/SiC, TiC, Ti3SiC2, ZnO, MnO2, carbon fibers, CNTs and graphene [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] .…”