Lightweight graphene aerogels by decoration of 1D CoNi chains and CNTs to achieve ultra-wide microwave absorption

Abstract

Hybrid aerogels combination of dielectric loss composition and magnetic loss constituent are supposed to be the appealing microwave absorption materials due to the synergy between dielectric and magnetic constituents, lightweight feature as well as multiple scattering. Herein, hybrid graphene aerogels with decoration of 1D CoNi chains and CNTs (GA-CNT-CoNi) were fabricated via a facile freeze-drying method and followed by thermal reduction. Compared with GA and GA-CoNi aerogels, 4 wt% GA-CNT-CoNi immersed in polydimethylsiloxane matrix reveals the strongest microwave absorption properties. The optimal reflection loss (RL) value is −50.8 dB at only thickness of 1.8 mm, and the effective absorption bandwidth (EAB, RL below −10 dB) can achieve 8.5 GHz (18–26.5 GHz) covering the whole K band. High ohmic loss induced by 3D macroscopic conductive network, multiple polarization as well as eddy current loss are responsible for the boosted microwave absorption. The results demonstrate that GA-CNT-CoNi aerogel reveals the characteristics of ultra-low filler content, strong absorption, ultra-wideband, small thickness and lightweight, which is considered as a promising microwave absorbing candidate.