Structural regulation of Co3O4/Nickel foam for enhanced electromagnetic wave absorption performance

In this work, distinct-morphological Co 3 O 4 /Nickel foams were prepared through a simple hydrothermal method and a subsequent heat treatment process. The morphology of Co 3 O 4 can be efficiently modulated from hexagonal nanosheets to nanobunches and urchin-like microspheres by manipulating the NH 4 F concentration. For the urchin-like Co 3 O 4 /Nickel foam composites, the minimum reflection loss (RL min ) value can reach −42.53 dB at a matching thickness of 2.7 mm. Theoretical analysis shows that the enhanced microwave absorption intensity is mainly originated from dielectric losses including significant interfacial polarization of the abundant interfaces, intrinsic dipoles of Co 3 O 4 and magnetic losses containing natural resonance and eddy current loss are favorable for the impedance matching. Simultaneously, multiple scattering occurring within the 3D Ni network skeleton are considered to promote the microwave absorption performance. Furthermore, a quadrilateral cone array of the resultant urchin-like Co 3 O 4 /Nickel foam composites has a RL min of −56.7 dB and an effective absorption bandwidth can achieve 9.44 GHz. This work could be beneficial for exploiting high-efficient magnetic-dielectric microwave absorption materials via the microstructural design.