Construction of hierarchical ZnO-NiCo2O4-NiCo2O4 core-shell microstructure with efficient microwave absorption

Core-shell structural design is an attractive strategy to achieve high-performance microwave absorbers. Nevertheless, it still remains a problem to simultaneously obtain superior microwave dissipation and impedance matching for microwave absorption (MA) materials. In this work, ZnO-NiCo 2 O 4 -NiCo 2 O 4 (ZNN) core–shell microstructure is designed and fabricated by covering NiCo 2 O 4 nanosheets on the surface of ZnO nanorod and next growth of NiCo 2 O 4 nanoparticles. With the synergies from the NiCo 2 O 4 nanosheets improving the microwave attenuation capability and the NiCo 2 O 4 nanoparticles increasing the impedance matching, ZNN possesses efficient MA performance: the strongest reflection loss is −59.93 dB at the corresponding thickness of 2.6 mm, and the maximum absorption bandwidth is 7.04 GHz at 2.4 mm, which covers the entire Ku-band. RCS simulation also indicates that ZNN has outstanding MA performance. Moreover, this study proposes a point for the utilization of nickel–cobalt oxides in MA materials, and offers a reference for the design of core–shell structural absorbers.