Joule-heated flexible carbon composite towards the boosted electromagnetic wave shielding properties

Electromagnetic interference materials simultaneously possessing high-performance EMI shielding and hydrophobic capability are significant in the sophisticated electronic devices. It still faces a great challenge to prepare the hydrophobic flexible materials with controllable EMI shielding properties. Herein, we proposed a novel voltage-driven Joule heating strategy to boost the EMI shielding properties of magnetic metals capsulated within carbon nanotube (CNT) arrays on carbon cloth. A lower driving voltage can quickly produce high temperature, reaching as high as 523 K under only 2.5 V. By stimulation of Joule heating, the electron movement including hopping and migration could be enhanced, and final EMI shielding properties are strengthened correspondingly. The EMI shielding effectiveness performances of the CNT (NiCo) arrays/carbon cloth increased from 57.2 dB at 0 V to 69.2 dB at 2.5 V, and absorption dominates EMI shielding capacity. In situ transmission electron microscopy was also conducted under various temperatures ranging from 298 to 573 K to consolidate the absorption mechanism. This strategy paves a useful way to design the hydrophobic flexible materials with external voltage-driven electromagnetic properties. Graphical abstract