Magnetic iongel/carbon nanotube composites for ultra-broadband electromagnetic wave absorption

Abstract

Organic magnets possess broad application prospects in electromagnetic wave (EW) absorbing materials (EAMs) due to their special electromagnetic properties, lightweight nature and good compatibility. Thus, in this paper, an innovative organic magnet, magnetic iongel (C₁₂IMSO₃[FeCl₄]), was successfully fabricated through the self-assembly of an alkyl long-chain imidazolium zwitterion (C₁₂IMSO₃) and a magnetic ionic liquid (Bmim[FeCl₄]). EWs were absorbed via various attenuating routes in C₁₂IMSO₃[FeCl₄], such as ionic conductive, polarization and magnetic loss. The minimum reflect loss (RL_min) and effective absorption bandwidth (EAB) of the C₁₂IMSO₃[FeCl₄] EW absorber could reach −35 dB and 1.8 GHz, respectively. After being combined with CNTs and further introducing strong electric conductive loss, the C₁₂IMSO₃[FeCl₄]/CNT composition showed more advanced EW absorption properties, especially in terms of the EAB; C₁₂IMSO₃[FeCl₄]/CNT achieved an EAB of 7.44 GHz at a small thickness of 2.2 mm. The ultra-broadband EW absorption performance of the C₁₂IMSO₃[FeCl₄]/CNT composite transcends many reported inorganic magnetic EW absorbing composites, providing a new approach to broadband EW absorbing materials.