Carbon-nanotube-based ultralight materials for ultrabroadband electromagnetic wave shielding and absorption

In this paper, we report ultralight carbon-nanotube (CNT)-infused materials with high electromagnetic shielding and absorption performance over an ultrabroadband frequency range. By controlling the CNT content and thickness of ultralight aerogels composed of CNTs during fabrication, their electromagnetic shielding/absorbing performance can be tuned over a wide frequency range (5.6–110 GHz). Samples with 40 wt% CNTs exhibit excellent shielding performance in an intensity range of 30–90 dB in all frequency ranges. Samples with less than 5 wt% CNTs show improved electromagnetic wave absorption performance of more than 10 dB. In addition, in samples with 2 and 4 wt% CNTs, strong absorption of over 25 dB occurs at certain frequencies. These CNT aerogels, which are ultralight (bulk density: 10 mg cm−3) and exhibit good mechanical properties, are expected to become a new material for electromagnetic shielding and absorption in advanced engineering applications.