Multi-mode tunable electromagnetic wave absorber based on hollow nano-cage structure and self-anticorrosion performance

In order to prevent electromagnetic interference, the standards for electromagnetic wave (EMW) absorption materials have tightened with the widespread growth of electrical communication equipment. Optimal EMW absorption performance may be achieved by prudent control of permittivity. Because of its outstanding dielectric property, controlled structure, and low cost of process, NiCo-based materials (NiCo 2 X 4 , X = O, S, Se, and Te) have been viewed as potential materials for absorbing electromagnetic waves. In particular, the presence of anionic sites has a significant impact on a material’s permittivity and conductivity. This work reports the effective hydrothermal preparation of NiCo 2 X 4 hollow nanoceras, followed by telluride, vulcanization, selenium, and oxidation processes. Owing to variations in the element electronegativity of anions, NiCo 2 Se 4 and NiCo 2 Te 4 exhibited enhanced conductivity and dielectric loss. An optimal reflection loss (RL) of Mn-NiCo 2 Se 4 at the matching thickness of 2.0 mm can reach −77.57 dB, and the effective absorption bandwidth (EAB) at the matching thickness of 2.0 mm is 4.88 GHz. The RL of Mn-NiCo 2 Te 4 at the matching thickness of 2.1 mm can reach −64.74 dB, and the EAB can reach 5.68 GHz at 2.0 mm. The samples made in this experiment also show maritime anticorrosion capabilities, which offers some research directions for the creation of materials with dual uses. It is anticipated that this research will offer significant new perspectives on the significant impacts of anionic coordination modulation on the EMA characteristics of composites made of transition metal matrix.