Fabrication of NiCo 2 -Anchored Graphene Nanosheets by Liquid-Phase Exfoliation for Excellent Microwave Absorbers

Graphene nanosheets (GNSs) were prepared by an efficient liquid-phase exfoliation method, and then the NiCo 2 /GNS nanohybrids were fabricated using the single-mode microwave-assisted hydrothermal technique. The NiCo 2 /GNS composites with different GNS proportions were investigated as microwave absorbers. Morphology investigation suggested that NiCo 2 nanocrystals were uniformly anchored on the GNS without aggregation. The electromagnetic parameters of NiCo 2 /GNS nanohybrids could be artificially adjusted by changing the GNS proportion, which led to an exceptional microwave-absorbing performance. A reflection loss (RL) exceeding −20 dB was obtained in the frequency range of 5.3–16.4 GHz for the absorber thicknesses of 1.2–3.2 mm, while an optimal RL of −30 dB was achieved at 11.7 GHz for a thickness of 1.6 mm. The enhanced microwave-absorbing performance indicated that the NiCo 2 /10 wt % GNS composite has great potential for use as an excellent microwave absorber.