Synergistically-enhanced flexible electromagnetic interference shielding nanocomposites

The unique three-dimensional architecture endows melamine-based carbon foam with many intriguing merits, including lightweight, good mechanical strength, high electrical conductivity, good chemical stability, flexibility, etc. Hence, this kind of carbon foam is thought to be a promising candidate for next-generation electromagnetic interference (EMI) shielding material. However, its practical application is restricted by its moderate EMI shielding property. In this work, we proposed multiple synergistic strategies to address this issue. Specifically, a Co3O4/carbon nanotubes (CNTs)/carbon foam composite was experimentally constructed using a facile synthetic process. The results indicated that the total EMI shielding effectiveness (SET) of the Co3O4/CNTs/carbon foam composite with a thickness of 3 mm could reach 25.6 dB in the frequency range of 8.2-12.4 GHz, which was about 10 dB higher than that of pristine carbon foam. Moreover, the compressive strength of the composite was much higher than that of pristine carbon foam, and it also delivered a higher EMI shielding performance retention even after 100 and 200 times bending, respectively. Lastly, the role of multiple synergistic effects of Co3O4 and CNTs in influencing the composite's EMI shielding performance was comprehensively discussed.