Ultralight heterostructured aerogels of ZnO/ZnFe2O4/Fe3O4/RGO/MWCNT for ultra-broadband microwave absorption

Abstract

Developing microwave-absorbing materials with wideband efficacy, low density, and minimal thickness remains a key challenge for electromagnetic interference shielding and stealth. This study unveils two ultralight aerogels prepared in parallel: a ZnO/ZnFe₂O₄/Fe₃O₄/RGO heterostructure and its MWCNT-reinforced counterpart (ZnO/ZnFe₂O₄/Fe₃O₄/RGO/MWCNT), the latter incorporating both GO and MWCNT simultaneously during synthesis. The optimized composite demonstrates extraordinary bandwidth performance, achieving a reflection loss (RL) below −10 dB across an exceptionally broad frequency range of 5.4 to 18 GHz, effectively covering 12.6 GHz of the measurable spectrum with matching thicknesses of just 1.4 to 4.0 mm. The formation of a synergistic conductive network between RGO and MWCNTs facilitates superior charge transport and dielectric loss, which is instrumental in realizing this ultra-wideband absorption. The central finding of this work is that the material's architecture successfully fulfills the dual criteria of excellent impedance matching and a high attenuation coefficient. The presented aerogel, with its remarkable bandwidth, represents a highly promising candidate for next-generation electromagnetic wave absorption applications.