Graphene/silver nanowire aerogel sponge for highly effective electromagnetic energy attenuation

The development of a highly effective microwave absorber with low filler loading remains a huge challenge. Herein, ultralight three-dimensional graphene/silver nanowire aerogel composites were prepared by a polyol and lyophilization method, and were employed as an effective filler in the fabrication of a high-performance electromagnetic wave absorber. The impedance matching was distinctly optimized by adjusting the ratio between the one-dimensional silver nanowires and two-dimensional graphene nanosheets of the composites, as well as the filler loading. A maximum reflection loss value of −50.25 dB and an effective absorption bandwidth of 5.95 GHz were obtained for the graphene/silver nanowire aerogel composite, with an ultra-low 5 wt% filler loading. The outstanding performance was mainly attributed to interfacial polarization caused by rich heterogeneous contact between the silver nanowires and graphene nanosheets, and internal multi-scattering absorption caused by abundant aerogel pores. This work offers a reliable method for fabrication of an ultra-lightweight aerogel-based microwave absorber with ultra-low filler loading for effective electromagnetic attenuation.