Abstract:

Although lightweight and three-dimensional (3D) graphene aerogels are highly desirable for microwave absorption (MA) due to their high porosity, specific surface area, and 3D conductive network, it still remains a large challenge to construct a multifunctional application framework to quickly adapt to the complex practical environment, making it to be efficiently applied in a variety of complex situation. Herein, multifunctional aramid nanofibers (ANFs) reinforced reduced graphene oxide aerogels (RGO@ANF) have been achieved by in-situ gel reaction, freeze-drying, and thermal annealing processes. The introduced ANFs in RGO aerogels can prevent the graphene sheets from over-stacking and enhance the connectivity of cell walls, thus leading to excellent compression resistance, MA, sound absorption, and thermal insulation performance. Under 70% strain, the maximum compressive stress of RGO@ANF aerogel reaches 78.8 kPa, and reversible compressibility with reliable resistance to fatigue for 100 compressive cycles at 20% strain. Further, the RGO@ANF aerogel exhibit a minimum reflection loss (RL_min) of -56.5 dB and a maximum effective absorption bandwidth (EAB) of 7.0 GHz at a thickness of 2.8 mm, basically covering the X and Ku bands. Moreover, the hybrid aerogel exhibited excellent sound absorption with an average absorption coefficient > 0.56 at 2-6 kHz and good thermal insulation performance with low thermal conductivity of about 49.18 mW m^-1 K^-1. The integrated graphene aerogels with such multifunctional performances hold a great promise for applications such as MA, sound absorption, and heat insulation.

Key words: Graphene-based aerogels, Reversible Compressibility, Microwave absorption, Heat insulation, Sound absorption