Abstract: With the rapid development of electronic information technology and wireless communication, electromagnetic pollution has become increasingly severe, creating an urgent need for high-performance electromagnetic wave absorbing materials. Microstructure regulation is a key approach to enhancing the electromagnetic response performance of absorbers. In this study, a novel structural regulation strategy based on chemical intercalation-induced phase transition was proposed. By intercalating layered transition metal dichalcogenide VSe₂ with metal atoms such as Fe, Co, and Ni, interlayer structural reconstruction and local lattice rearrangement were induced, thereby achieving tunable and optimized electromagnetic properties. The results show that at low intercalation doses, the intercalation products retain the original crystal structure of VSe₂; at high intercalation doses, however, the strong affinity between Fe, Co, Ni and Se causes distortion of the octahedral structural units in VSe₂, leading to the formation of a secondary phase M_0.5VSe₂ (M = Fe, Co, Ni) using VSe₂ as the lattice template. Further studies have revealed that metal intercalation can effectively modulate the electronic structure and interfacial characteristics of the material. With increasing intercalation ratio, the impedance matching characteristics of the material are progressively improved, while the polarization loss is enhanced and the dielectric loss capability is elevated. When a stable M_0.5VSe₂ (M = Fe, Co, Ni) phase structure is formed, the material exhibits excellent electromagnetic wave absorption performance even at relatively thin thicknesses. For instance, the Co-intercalated reaction product Co_0.5VSe₂ shows significantly improved absorption performance in the 8.2-12.4 GHz frequency range compared with VSe₂, achieving a maximum effective absorption bandwidth of 2.84 GHz at a sample thickness of 1.68 mm, and a minimum reflection loss of -60.10 dB (at 9.45 GHz) at a thickness of 1.84 mm. This study confirms the effectiveness of the intercalation-induced phase transition strategy in optimizing the electromagnetic properties of layered materials, and provides new insights and experimental evidence for the structural design and absorption performance enhancement of layered transition metal dichalcogenides.

Key words: vanadium diselenide (VSe₂), metal intercalation, phase transition regulation, electromagnetic property, electromagnetic wave absorption performance