The absorption frequency of conventional microwave absorbing materials (MAMs) is hardly tuned in operando, while such dynamic frequency regulation of MAMs is of great significance to meet the high demands of modern radars and intelligent electron devices. Here, an ingenious frequency-tuning strategy by means of the pressure variations is developed by fabricating highly compressible carbon nanocoils/carbon foam (CNCs/CF) as a dynamically frequency-tunable microwave absorber. Through adjusting the compression strain, the absorption bandwidth of CNCs/CF can be precisely tuned from S-band (2−4 GHz) to Ku-band (12−18 GHz). The adjustable effective absorption bandwidth is as wide as 15.4 GHz, which covers 96% of the entire microwave frequency. Under 10% compression strain, CNCs/ CF shows an attractive bandwidth of 9.0 GHz and a strong reflection loss of −64.6 dB. Furthermore, the CNCs/CF also exhibit a good thermal insulation, strong hydrophobicity, and strain-sensitive conductivity, endowing them with fascinating functions of heat insulation and self-cleaning. The method of utilizing an external pressure to dynamically adjust the absorption frequencies of CNCs/CF is demonstrated for the first time, which opens an avenue for the applications of dynamically frequency-tunable MAMs with an ultrawide adjusting range and absorption bandwidth.

Heat-conduction microwave absorbers with outstanding electromagnetic wave (EMW) absorption and thermal management performance are considerably attractive in the field of modern electronic devices. Herein, by uniformly depositing aromatic polyimide (PI)...

Electromagnetic interference (EMI) shielding and electromagnetic wave absorption (EWA) materials with good thermal management and flexibility properties are urgently needed to meet the more complex modern service environment, especially in the field of smart wearable electronics. How to balance the relation of electromagnetic performance, thermal management, flexibility, and thickness in material design is a crucial challenge. Herein, graphene nanosheets/aramid nanofiber (C-GNS/ANF) carbonizing films with nacre-like structures were fabricated via the blade-coating/carbonization procedure. The ingenious configuration from highly ordered alignment GNS interactively connected by a carbonized ANF network can effectively improve the thermal/electrical conductivity of a C-GNS/ANF film. Specifically, the ultrathin C-GNS/ANF film with a thickness of 17 μm shows excellent in-plane thermal conductivity (TC) of 79.26 W m–1 K–1 and superior EMI shielding up to 56.30 dB. Moreover, the obtained C-GNS/ANF film can be used as a lightweight microwave absorber, achieving excellent microwave absorption performance with a minimum reflection loss of −56.07 dB at a thickness of 1.5 mm and a maximum effective absorption bandwidth of 5.28 GHz at an addition of only 5 wt %. Furthermore, the C-GNS/ANF films demonstrate good flexibility, outstanding thermal stability, and flame retardant properties. Overall, this work indicates a prospective direction for the development of the next generation of electromagnetic wave absorption/shielding materials with high-performance heat conduction.

In this work, inspired by the great advantage of the unique “brick‐mortar” layered structure as electromagnetic interference (EMI) shielding materials, a multifunctional flexible graphene nanosheets (GNS)/polytetrafluoroethylene (PTFE) composite film with excellent EMI shielding effects, impressive Joule heating performance, and light‐to‐heat conversion efficiency is fabricated based on the self‐emulsifying process of PTFE. Both PTFE microspheres and nanofibers are employed together for the first time as “sand and cement” to build unique nacre‐structured EMI shielding materials. Such configuration can obviously enhance the adhesion of composites and improve their mechanical property for the application under extreme environment. Moreover, the simple and effective repetitive roll pressing method can be used for the scalable production in industrialization. The GNS/PTFE composite film shows a high EMI shielding effectiveness (SE) of 50.85 dB. Furthermore, it has a high thermal conductivity of 16.54 W (m K)−1, good flexibility, and recyclable properties. The excellent fire‐resistant and hydrophobic properties of GNS/PTFE film also ensure its reliability and safety in practical application. In conclusion, the GNS/PTFE film demonstrates the potential for industrial manufacturing, and outstanding EMI shielding performance with high stability and durability, which has a broad application prospect for electronic devices in practical extreme outdoor environments.

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