Tunable electromagnetic wave absorption properties of nickel microspheres decorated reduced graphene oxide

The composites of nickel microspheres decorated reduced graphene oxide (NG) with extraordinary electromagnetic absorption properties were fabricated via a facile one-step solvothermal reduction approach. The morphology characteristics suggest that nickel microspheres loaded on both reduced graphene oxide (RGO) sheet sides can prevent sheets from restacking, in turn, RGO network can also inhibit the agglomeration of nickel particles. The electromagnetic parameters reveal that the samples exhibit tunable electromagnetic absorption properties through adjusting the initial concentrations of nickel salt. With the matching thickness of 1.2 mm, the reflection loss (RL) of NG-1 achieves -31.4 dB at 14.5 GHz, and the effective absorption band (RL <-10 dB) ranges from 13.3 to 16.0 GHz. Besides, the optimal RL of NG-2 and NG-3 can reach -35.4 dB at 8.2 GHz and -49.0 dB at 5.3 GHz, respectively. Furthermore, the excellent electromagnetic wave absorption capability can be reasonably interpreted by the impedance matching characteristics and the quarter-wavelength attenuation model. The hybrids of nickel microspheres and RGO flakes in this work are hopeful to serve as attractive electromagnetic absorption materials, which can realize strong and broad effective absorbing at thin matching thickness.