Nanointerface engineering of cobalt sulfide/manganese sulfate hollow spheres for electromagnetic wave absorption

Highlights: • CoS/MnSO₄ heterostructure with hollow flower-like structure is fabricated. • Numerous nanointerfaces are formed in the heterostructure. • The heterostructure exhibits excellent electromagnetic wave absorption property. The CoS/MnSO₄ heterostructure with hollow flower-like structure (Co-Mn-S) is fabricated through a facile method. The microspheres have diameters of 1 – 2 µm, composed of CoS and MnSO₄·5H₂O nanoflakes. The numerous nanointerfaces are formed due to the tight contact of MnSO₄·5H₂O nanoflakes with the CoS nanoflakes. The CoS/MnSO₄ heterostructure exhibits excellent electromagnetic wave absorption property with strong attenuation abilities and thin thickness. The minimal reflection loss reaches −48.0 dB at 12.4 GHz and the efficient absorption bandwidth is 3.8 GHz (10.7–14.5 GHz) with a filler loading 30 wt% at the thin thickness of 2.0 mm. In addition, even in the thin thickness (1.5–2.0 mm), the minimum reflection loss of the micro-nanostructure can reach –20 dB, and the efficient absorption bandwidth is 4.3 GHz at the thickness of 1.7 mm. The experimental and density functional theory calculation results indicate that the excellent electromagnetic wave absorption property of the heterostructure is ascribed to better impedance matching characteristic and enhanced dielectric loss, caused by its hollow structural feature and the interfacial polarization at the nanoscale level.