Enhanced Interfacial Polarization Loss of FeS/MoS₂@N‐Doped Carbon Sandwich‐Walled Nanotubes Enables High‐Performance Electromagnetic Wave Absorption

Abstract Multiple interfaces and hollow structures are vital to high‐performance electromagnetic wave (EMW) absorption of absorbers. However, it remains difficult to construct and tune such structures, and there is limited understanding regarding the relationships between their structural and dielectric loss properties. Herein, the theoretical simulations for the EMW absorption performance of the hollow sandwich and solid double‐layer structures are first carried out and it is found that the former exhibits a more pronounced power loss density than the latter. Then, a ligand‐exchange strategy following a vulcanization process to fabricate FeS/MoS 2 @N‐doped carbon sandwich‐walled nanotubes (FeMoS‐SWCNTs) is dveloped. The experimental results demonstrate that the FeMoS‐SWCNTs show significantly enhanced EMW absorption performance compared to the solid FeS counterparts, consistent with the simulation results. Further density functional theory calculations reveal that the enhanced dielectric properties of FeMoS‐SWCNTs are attributed to a stronger interfacial polarization resulting from electronic interactions at multiple interfaces (FeS/N‐doped carbon (NC), MoS 2 /NC, and FeS/MoS 2 ), and enhanced conduction loss caused by higher density of states in the FeS/MoS 2 heterostructure. These findings elucidate the relationship between the sandwich‐walled nanotube structures and their dielectric loss properties, and the developed method offers a feasible approach for the rational design of sandwich‐walled nanotubes for high‐performance EMW absorption applications.