Nanolayered Ceramic-Confined Graphene Aerogel with Conformal Heterointerfaces for Low-Frequency Microwave Absorption.

Abstract

Graphene-based aerogels have garnered considerable attention for their lightweight and efficient microwave absorption (MA) properties; however, optimizing the relationship between impedance matching and attenuation capability at low frequencies remains a challenge. In this study, a three-dimensional (3D) silicon carbonitride (SiCN) nanoceramic-coated graphene aerogel with conformal heterogeneous interfaces is constructed by precursor infiltration and pyrolysis to optimize MA performance at low frequencies. Thanks to the enhanced impedance matching and significant interfacial polarization of the two-dimensional sandwiched SiCN/graphene/SiCN cell walls and multiple scattering occurring within the 3D porous skeleton, the aerogel achieves a minimum reflection loss of -57.9 dB at an ultralow frequency of 4.92 GHz (C-band) and a broad bandwidth of 5.0 GHz at an ultralow thickness of 1.7 mm. The strategy developed here provides a method for enhancing dielectric polarization loss in graphene aerogels by the joint optimization of interfacial polarization and impedance matching, inspiring the design of high-performance graphene-based materials for low-frequency MA.