Sandwich-structure CNT-graphene film with covalent bond for high-performance electromagnetic shielding and thermal management

Macro-assembled graphene-based films can been considered as a potential material for the electromagnetic shielding (EMI) and thermal management in portable electronics. Here, a carbon nanotubes and graphene composite film with covalent bond (CNT-gGF) was fabricated through graphitized welding. The fabricated covalent-bonding CNT-gGF was featured with sandwich structure based carbon nanotubes welding graphene layers as the skeleton, resulting in an excellent conductivity of 13000 S cm⁻¹ exceeding the pure graphene film. These unique structures endow CNT-gGF film with a prominent mechanical property and flexibility (folding resistant with 1000 cycles). Importantly, an outstanding EMI value is over 55 dB with a thickness of merely 20 μm in the broad frequency of 5–22 GHz. And the CNT-gGF was proven to exhibit a steady EMI property in a variety of extreme environments including high and low temperatures and burns. Moreover, the thermal conductivity of CNT-gGF could be up to 912 W m⁻¹ K⁻¹, then CNT-gGF presents well heat dissipation application for different voltages and mobile phone. Therefore, this large-size CNT-gGF film has a good application potential for high-performance EMI and thermal management, and this study provides favorable guidelines for the graphene-based films toward extreme demands in wearable electronics and 5G communication.