Defect-rich Co–MoS 2− x O x @NC fiber heterostructures derived from in situ grown metal-organic frameworks towards high electromagnetic wave absorption

Defect-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies provide a promising strategy to boost electromagnetic wave (EMW) absorption. However, challenges remain in precisely controlling the balance between construction and the electromagnetic loss mechanism. In this study, an innovative Co-MoS_2-xO_x@NC core-shell fiber with multiple loss mechanisms was synthesized through an in situ growth and carbonization process. This structure ingeniously combines ZIF-67 with a carbon fiber (CNF) conductive network to form continuous conductive pathways, providing an ideal medium for conduction loss. Simultaneously, Co ions embedded between MoS₂ layers induce strong lattice distortion and abundant vacancies, forming numerous heterointerfaces between Co, MoS₂, and the CNF. Significant differences in electron density and charge redistribution at the interface greatly enhance interfacial polarization loss. The stacked MoS₂ nanosheets extend the transmission path of EMWs, dissipating electromagnetic energy by enhancing multiple reflections and scattering. Consequently, Co-MoS_2-xO_x@NC fibers achieve strong EMW absorption with a minimum reflection loss of -66.43 dB at 1.98 mm and a wide effective absorption bandwidth of 5.80 GHz at 1.87 mm. This study highlights synergistic effects of lattice vacancies and heterogeneous interfaces, offering a promising solution for constructing an advanced CNF matrix wave-absorbing material.