Synergistic polarization loss of binary metal selenides for enhancing electromagnetic wave absorption

The development of multi-component dielectric composites has become the major method to obtain excellent electromagnetic wave (EMW) absorbing materials. However, traditional ways of component introduction are often complicated and uncontrollable, and lack the regulation of components, interfaces and defects. In this paper, the Mo-based binary metal selenides (Mo-M selenides) with flower-like hollow structure was prepared controllably by introducing competing ions during the preparation of MoSe 2 . By changing the concentration and species of competing ions to regulate the composition, defects and interface, the electromagnetic wave absorption performance of Mo-M selenide can be adjusted. Multiple components, rich heterointerfaces and defects achieved perfect impedance matching and multiple polarization loss, improving the EMW absorption performance. The minimum reflection loss (RL min ) of Mo-Fe(0.08) selenides reached -60.4 GHz, and the effective absorption bandwidth (EAB) covered the entire X-band at 2.9 mm. Moreover, the EAB of Mo-Fe(0.12) selenides at 1.9 mm was 5.9 GHz, covering almost the entire Ku-band. Other Mo-M selenides also exhibited excellent EMW absorption properties. This work not only proposed a new idea to study the comprehensive effects of interfaces, components, and defects on electromagnetic wave absorption, but also provided a simple and controllable method for constructing efficient composite absorbers. • A controllable method for constructing efficient composite absorbers is developed. • The Mo-M selenides with abundant heterointerfaces and defects have hollow structure. • The EAB of Mo-Fe(0.12) selenides covers 5.9 GHz at a thin thickness of 1.9 mm. • Electromagnetic parameters are adjusted by changing concentration and species of M n+ .