Constructing Hierarchical Porosities Strategy Toward Graphene Aerogels for Lightweight and Broadband Microwave Absorbing

Abstract

Graphene aerogels have shown fabulous capability in microwave absorption (MA) because of their high surface area, low density, and great chemical stability. To fully exploit its MA capability, the microstructural regulation of graphene aerogels should be carefully studied. Herein, we prepared three-dimensional holey reduced graphene aerogels (3D-HGA) with hierarchical porosity structures composed of micropores and mesopores in the plane of graphene oxide sheets and macropores in aerogel for high-performance absorbing materials. The efficient absorption bandwidth (EAB) can reach 7.1 GHz and the minimum reflection loss is -36.4 dB, showing a significant increase contrasted with 3D reduced graphene oxide aerogels (3D-RGA). Hierarchical porosity, interfacial polarization, multiple reflections, and matched impedance all contribute to improving microwave absorption performance. Consequently, the low filling content (5 wt%), low density (7.47-8.84 mg/cm 3 ), and special hierarchical porosity inspire the design of high-performance radar absorption.

Keywords: Polymers, Oxide materials, atomic scale structure, Microstructure.