Construction of Hierarchical Yolk–Shell Co/N-Dope C@void@C@MoS2 Composites with Multiple Heterogeneous Interfaces toward Broadband Electromagnetic Wave Absorption

The synthesis of materials with a multicomponent hierarchical structure is an essential strategy for achieving high-performance electromagnetic wave (EMW) absorption. However, conventional design strategies face challenges in terms of the rational construction of specific architecture. In this study, we employ a combined space-restricted and hierarchical construction strategy to surface-plant MoS2 nanosheets on yolk–shell structural carbon-modified Co-based composites, leading to the development of high-performance Co/NC@void@C@MoS2 absorbers with advanced architecture. The surface-planted MoS2 nanosheets, the Co/NC magnetic yolk, and the dielectric carbon shell work together to enhance the impedance matching characteristics and synergistic loss capabilities in the composites. Experimental results indicate that Co/NC@void@C-700@MoS2 exhibited the best absorption performance with an effective absorption bandwidth of 7.54 GHz (at 2.05 mm) and a minimum reflection loss of −60.88 dB (at 1.85 mm). Furthermore, radar cross-section simulation results demonstrate that Co/NC@void@C-700@MoS2 effectively suppresses the scattering and transmission of EMWs on perfect electric conductor substrates, implying its superior practical application value. This study provides inspiration and experimental basis for designing and optimizing EMW absorption materials with hierarchical yolk–shell architecture.