Design of spinous Ni/N-GN nanocomposites as novel magnetic/dielectric microwave absorbents with high-efficiency absorption performance and thin thickness

Elaborately constructing magnetic/dielectric nanocomposites is believed to be an efficient pathway to enhance the microwave absorption performance of microwave absorbers. We reported a straightforward one-pot solvothermal route to fabricate spinous Ni grown on N-GN as fascinating magnetic/dielectric microwave absorbents. Ni nanostructures show spinous shape, which are regularly decorated on N-GN. Benefiting from the synergistic effect of magnetic spinous Ni nanostructures and dielectric lightweight N-GN, the N-GN/Ni nanocomposites possess tremendously increased microwave absorption characteristics. The N-GN/Ni nanocomposites exhibit a maximum RL of − 47.1 dB at 13.6 GHz when the thickness is only 1.6 mm, which is about 3 times larger than that of bare Ni. In particular, the effective absorption bandwidth (RL ≤ − 10 dB) of N-GN/Ni nanocomposites at 1.6 mm can reach 3.9 GHz ranging from 11.6 to 15.5 GHz. When the thickness is 1.1–5.0 mm, N-GN/Ni nanocomposites show a broad effective absorption bandwidth (RL ≤ − 10 dB) of 15.5 GHz ranging from 2.5 to 18 GHz, whereas the effective absorption bandwidth of bare Ni is only 0.7 GHz. The improved microwave absorption performance of N-GN/Ni nanocomposites is related to better impedance matching condition and higher attenuation capacity. The N-GN/Ni nanocomposites, which possess thin thickness, lightweight, strong absorption and broad bandwidth, are believed to have great potential as novel high-efficiency microwave absorbers.