Nanowires/nanohelices hybrid carbon aerogels as the lightweight and hydrophobic microwave absorbers with excellent electrothermal properties

Abstract

To extend the operational life of electronic equipment under a complex environment and introduce protection for human health against electromagnetic pollution, it is urgent to construct lightweight microwave absorption materials (MAMs) with hydrophobicity and electrothermal properties. Herein, we have fabricated creatively the nanowires/nanohelices hybrid carbon (CNWs/CNHs) aerogels via growing and carbonizing nanohelices in bacterial cellulose (BC) matrix, forming intertwined and interconnected conductive network. In addition, we investigated systematically the detailed structure and microwave absorption mechanism of the new type of CNWs/CNHs aerogels. Such novel structure was found to promote multiple relaxation and interface polarization due to the electromagnetic cross polarization, which in turn ameliorates remarkably the microwave absorption intensity and broadens the effective absorption bandwidth (EAB). The optimal CNWs/CNHs aerogels can show an excellent microwave absorption intensity of −56.90 dB at 13.76 GHz at a filling content of 5 wt%, and extend its maximum EAB to 6.32 GHz at a thickness of just 2.00 mm. At the same time, the CNWs/CNHs aerogels also have a superior self-cleaning function and a good electrothermal conversion performance. Therefore, the CNWs/CNHs aerogels may be adopted as the lightweight and hydrophobic MAMs with excellent electrothermal properties to satisfy the practical applications in complex low-temperature environment.