In-situ hydrothermal synthesis of NiCo alloy particles@hydrophilic carbon cloth to construct corncob-like heterostructure for high-performance electromagnetic wave absorbers

[Display omitted] •NiCo-APs@HCC composites were synthesized following the in-situ hydrothermal method.•NiCo-APs@HCC composites possess a unique corncob-like structure.•The EMW absorption performance can be adjusted by changing the Ni/Co ratio.•The optimal RLmin of NiCo-APs@HCC was −41.80 dB at a thickness of 2.29 mm.•The maximum EAB of NiCo-APs@HCC was 5.8 GHz, spanning almost the whole Ku band. NiCo alloy particles (NiCo-APs)@hydrophilic carbon cloth (HCC) composites were successfully prepared by uniformly decorating magnetic NiCo-APs on the surface of three-dimensional HCC by employing an in-situ hydrothermal method. The NiCo-APs@HCC composites exhibited a unique corncob-like network structure that helped improve the electromagnetic wave (EMW) absorption performance of composites. The EMW absorption properties of the composites could be controlled by altering the Ni/Co molar ratio. The optimal minimum reflection loss (RLmin) of −41.80 dB was achieved with the NiCo-APs@HCC composite thickness of 2.29 mm. The effective absorption bandwidth (EAB) reached the maximum of 5.8 GHz, spanning nearly the entire Ku band. In addition, the improved EMW absorption performance was further promoted by favorable impedance matching, strong conduction loss, magnetic loss, dipole polarization, interface polarization, multiple reflections, and scattering. A novel strategy for designing magnetic metal/carbon matrix composites with excellent EMW absorption performance is reported in this study.