1D CNT-Expanded 3D Carbon Foam/Si₃N₄ Sandwich Heterostructure: Utilizing the Polarization Compensation Effect for Keeping Stable Electromagnetic Absorption Performance at Elevated Temperature

Abstract

Modern electromagnetic (EM) absorbing materials (EAMs) are experiencing a revolution triggered by advanced information technology. Simultaneously, the diverse harsh EM application scenarios entail a more stringent appeal of practicability to EAMs, especially under high-temperature conditions. Therefore, exploring EAMs with both excellent absorbing performance and practicability at elevated temperatures is necessary. Herein, a novel 3D porous carbon foam/carbon nanotubes@Si3N4 (CF/CNTs@Si3N4) heterostructure was constructed by the chemical vapor infiltration process. The optimally grown 1D CNTs embedded in 3D CF/Si3N4 are utilized to provide abundant nanointerface coupling effects to compensate for the excessive increase in the conductive loss during rising temperature to realize a self-adjustment in response to high temperature. A high-efficiency EM absorption over a wide temperature range from 25 to 480 °C was achieved (with a ≥90% absorbing ratio covering the whole X-band). In addition, the Si3N4 coating can improve the thermal stability of the carbon matrix and maintain the tailored inner structure. Multiple investigations into other environmental adaptabilities also exhibited the application perspective of such a heterostructure. This work points out a new strategy for preparing designable, efficient, and high-temperature applicable EAMs, promoting the diverse development of electronic devices.

Microstructure controllable polyimide/MXene composite aerogels for high-temperature thermal insulation and microwave absorption

“…Cheng et al 44 made a biomass-derived porous carbon material with a RL min of −46.9 dB and an EAB of 6.2 GHz. Although attractive microwave absorption performance was achieved, 46–49 these materials face two critical issues. First, these porous absorbers were derived from carbon-based materials, which had high intrinsic thermal conductivity.…”

“…From a search of the literature, very few studies were carried out by simultaneously considering microwave absorption and thermal insulation properties in a thermal environment. Lu et al 47 fabricated CF/CNT@Si 3 N 4 hybrids, which displayed a RL min of −46.8 dB and an EAB of 4.0 GHz. Jiao et al 48 made a polymethacrylimide (PMI)/carbon fiber structure, exhibiting a RL min of −15.3 dB and an EAB of 4.0 GHz.…”

“…Journal of Materials Chemistry CPaper Lu et al47 fabricated CF/CNT@Si 3 N 4 hybrids, which displayed a RL min of À46.8 dB and an EAB of 4.0 GHz. Jiao et al48 made a polymethacrylimide (PMI)/carbon fiber structure, exhibiting a RL min of À15.3 dB and an EAB of 4.0 GHz.…”

Structure Design, Surface Modification, and Application of CNT Microwave‐Absorbing Composites

“…The RL value for a nanocomposite containing 0.75 wt% L-MWCNTs is ≈24.37 dB. [196] Lu et al [197] prepared a novel 3D porous carbon foam/CNT@Si 3 N 4 (CF/CNTs@Si 3 N 4 ) heterostructure by chemical vapor permeation, and the sandwich structure of the sample is shown in Figure 12a. Self-regulation to high temperatures is achieved by using optimally grown 1D CNTs embedded in 3D CF/Si 3 N 4 to provide a rich nano facial coupling effect to compensate for the excessive increase in conductance loss at elevated temperatures.…”

Construction of Hollow Carbon Nanofibers with Graphene Nanorods as Nano-Antennas for Lower-Frequency Microwave Absorption

“…Recent studies have proven that 1D carbon phases with a high graphitization degree, like CNTs, can transport EM wave energy efficiently. − Moreover, the restricted motion of electrons in CNTs weakens the skin effect, which makes CNTs suitable for nano-antennas. − By constructing these CNT-based nano-antennas in absorbers, EM waves can be guided into the interior of materials to optimize impedance match conditions. For example, sea urchin-like Co 3 ZnC/Co/CNT composites were prepared based on ZIF-67 particles.…”