Facile synthesis and microwave absorption properties of yolk-shell ZnO-Ni-C/RGO composite materials

Yolk-shell ZnO-Ni-C wrapped with reduced graphene oxide (RGO) hybrid structures were successfully fabricated by annealing treatment of amorphous yolk-shell zinc-nickel microspheres precursor. The special structures possessing core@void@shell configuration have excellent electromagnetic (EM) wave absorption properties, owing to void space could adjust impedance mismatching. Meantime, the RGO-wrapped yolk-shell ZnO-Ni-C microspheres increased the content of defects and generated more effective interfacial polarization response to EM wave radiation. As a result, the minimum value of reflection loss (RL) of ZnO-Ni-C/RGO is -59.3 dB at 15.2 GHz with a thickness of 2.05 mm and the effective attenuation bandwidth is in a broad range from 12.4 to 18 GHz.