Broadband microwave absorption of sandwich-like RGA/CNP/RGA composites under strong polarization relaxation at multiscale interfaces

Microwave-absorption materials play effective roles in resolving electromagnetic radiation, electromagnetic interference, and electromagnetic leakage. However, their narrow absorption bandwidths made it difficult to satisfy their actual application. Herein, we developed multilayered RGA/CNP composites consisting of paraffin-based reduced graphene oxide aerogels (RGAs) and PVDF-based hierarchical CoNi chains (CNPs); moreover, tailoring the layers optimized the microwave absorption properties of the composites. Interestingly, sandwich-like RGA/CNP/RGA composites exhibit outstanding microwave absorption performance with a minimum reflection loss (RL) of −48.03 dB and a maximum effective absorption bandwidth (EAB) of 7.14 GHz (10.86-18.00 GHz). The simulated RCS values are lower than −10 dB m² in the scattering angular range of −90° to 90°. Furthermore, the involved electromagnetic parameters were analyzed, and the possible microwave absorption mechanism of the RGA/CNP/RGA structure was revealed. The excellent microwave absorption performance of the composites is mainly ascribed to strong polarization relaxations, which may originate from the multiscale interfaces of RGA/CNP/RGA. Therefore, constructing sandwich-like dielectric-magnetic-dielectric structures would be a novel strategy for extending microwave absorption bandwidths.