Facile synthesis of NixCo3-xS4 hollow nanoprism with broader electromagnetic absorption properties: Effect of Ni/Co atomic ratios

Highlights: • Hollow Ni_xCo_3-xS₄ nanoprisms were prepared by a simple two-steps method. • The absorption property is tunable by controlling the atomic ratios of Ni/Co. • The effective absorption width can reach 5.6 GHz with a thickness of 2.0 mm. A suitable component with a benefited morphology is crucial to ensure the good electromagnetic absorption (EA) ability if used as electromagnetic absorber to deal with the severe electromagnetic interference crisis. In this research, Ni_xCo_3-xS₄ hollow nanoprisms with tunable Ni/Co molar ratios have been successfully prepared through a simple liquid reflux and subsequently conducting a sulfidation reaction. The morphologies, crystal phase structures were analyzed by X-ray diffraction (XRD), and transmission electron microscopy (TEM). As revealed by TEM, the Ni_xCo_3-xS₄ displayed hollow nanoprism shape with an average length of 1.2 μm, width of 100 nm and edge thickness of 13 nm, respectively. Afterward, the electromagnetic absorption abilities of these Ni_xCo_3-xS₄ products at various x values (x = 0.2, 0.5, 0.8) were investigated in terms of the theory of transmission lines. The results demonstrated that the bandwidth ((RL ≤ −10 dB) with a specimen thickness of 2.0 mm could cover 5.6 GHz when x∼0.5, which is much greater than Ni_0.2Co_2.8S₄ and Ni_0.8Co_2.2S₄ filling layers. The electromagnetic loss mechanism was discussed in depth, which was correlated with molar ratios, and unique hollow nanoprism structure.