Powerful and lightweight electromagnetic-shielding carbon nanotube/graphene foam/silicon carbide composites.

• SiC is modified by graphene foam and carbon nanotube for electromagnetic shielding. • Interconnected conductive graphene network sharply increases the electric loss. • Rich structural defects and multiscale interfaces generate extra polarization loss. • Modified SiC shows lightweight and excellent electromagnetic shielding performance. Carbon nanotube/graphene foam/silicon carbide (CNT/GF/SiC) composites are prepared by in-situ growth of CNT in GF and followed by infiltration and pyrolysis of CNT-dispersed polycarbosilane. Results show that the CNT/GF/SiC composites exhibit outstanding electromagnetic interface (EMI) shielding effectiveness (SE) of 32.1 dB in X-band, especially the specific SE reaches up to 33.8 dB cm3/g with a low density of 0.95 g/cm3. The interconnected conductive graphene network improves the conductivity and sharply increases electric loss; meanwhile, the rich structural defects and multiscale interfaces including GF-CNT interface and CNT-SiC interface offer additional polarization loss, both of which endow composites with outstanding EMI shielding performance. [ABSTRACT FROM AUTHOR]