Flexible and Ultrathin Graphene/Aramid Nanofiber Carbonizing Films with Nacre-like Structures for Heat-Conducting Electromagnetic Wave Shielding/Absorption

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 mu m 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.

Automated summary

This study fabricated graphene nanosheets/aramid nanofiber (C-GNS/ANF) carbonizing films with nacre-like structures through the blade-coating/carbonization procedure, which exhibit excellent thermal conductivity and electromagnetic interference (EMI) shielding performance. The thin C-GNS/ANF film with a thickness of 17 μm shows a high thermal conductivity of 79.26 W m-1 K-1 and superior EMI shielding up to 56.30 dB. It can also serve as a lightweight microwave absorber, achieving excellent microwave absorption performance with a minimum reflection loss of -56.07 dB and a maximum effective absorption bandwidth of 5.28 GHz at an addition of only 5 wt%.