Interface engineering of lightweight rGO@SiO2 for excellent microwave absorption

Herein, SiO2 is distributed uniformly on the surface of Graphene oxide (GO) by chemical crosslinking, and then the lightweight reduced graphene oxide@SiO2 (rGO@SiO2) (0.083 g/cm3) microwave absorption material (MWAM) was prepared by heat treatment. Benefiting from the heterogeneous interface between rGO and SiO2, the impedance matching of rGO@SiO2 is regulated well and the polarization losses of rGO@SiO2 such as dipole polarization, interfacial polarization and multiple reflections were enhanced. Therefore, the rGO@SiO2 exhibits excellent microwave absorption property, when the thickness of rGO@SiO2 is 1.5 mm, the minimum reflection loss (RLmin) of rGO@SiO2 is -54.08 dB. When the thickness of rGO@SiO2 is 1.7 mm, the effective absorption bandwidth (EAB) of rGO@SiO2 can reach 5.12 GHz. Moreover, the rGO@SiO2 rubber patch was prepared to verify its practical application performance and compare it with the simulation test results. This work provides a new approach for the design and application of rGO@SiO2 as the lightweight MWAM.