Spherical shape Co@Co3O4 core-shell composites grown on surface of graphite nanosheets with ultra-thin and excellent electromagnetic absorption performance

Abstract

In this work, graphite nanosheets (GNs)/Co composites with excellent electromagnetic (EM) absorption performance was designed by a one-step hydrothermal method, and the surface of Co particles were coated with Co3O4 shell layer by a second hydrothermal method to obtain the expected core-shell GNs/Co@Co3O4 structure, and the microtopography, structure and magnetic properties of core-shell GNs/Co@Co3O4 structure were characterized in detail. EM analysis revealed that core-shell GNs/Co@Co3O4 structure has an excellent EM wave absorption performance. For GNs/Co@Co3O4, the excellent reflection loss (RL) is −55.16 dB with an ultra-thin matching thickness of 1.6 mm, and the effective absorption bandwidth (EAB) is 3.84 GHz (from 14.16 GHz to 18.00 GHz) with the ultra-thin matching thickness of only 1.2 mm. In this work, the two hydrothermal methods replaced the conventional core-shell structure method and obtained EM wave absorption core-shell Co@Co3O4/GNs with ultra-thin thickness, strong EM wave absorption capability, and broad absorption bandwidth.