Entropy engineering enhances the electromagnetic wave absorption of high-entropy transition metal dichalcogenides/N-doped carbon nanofiber composites

Abstract

Entropy engineering strategies provide a broader platform for exploring the behavior of electromagnetic wave (EMW) absorption materials and their absorption mechanisms on the microscopic scale. In this work, a novel entropy engineering strategy was developed to improve the EMW absorption properties of MoS₂. A hierarchical N-doped carbon nanofiber/MoS₂ (NCNF/MS) composite was synthesized using the electrospinning and hydrothermal methods. Then, the conformational entropy of MoS₂ was increased by sequentially integrating elements such as W, Se, and Te. Although MoS₂ maintains a single 2H-phase structure throughout the entropy increase process, it triggers a series of complex changes at the microscopic level, including lattice distortion, ingenious electronic structure adjustments, and an increase in defect density. These changes provide more possibilities for the EMW interaction with the absorber, which significantly enhances the dielectric behavior of the composites, including conduction and polarization losses. Owing to the unique hierarchical structure and rich defect structure, the obtained entropy-increased NCNF/MWSST exhibits excellent EMW absorption performance. The minimum reflection loss reaches −60.7 dB, and the maximum effective absorption bandwidth is 6.48 GHz, which is improved by almost 584% and 810% compared to NCNF/MS. This study provides a new way to design efficient and high-performance MoS₂-based absorbers and provides valuable insights for exploring the entropy-increasing strategies to optimize the EMW absorption properties.