Construction of multidimensional heterointerfaces in Fe-MXene decorated carbon fibers for enhanced broadband low-frequency microwave absorption

Although carbon fibers (CFs) are widely favored for their light weight, superior electrical properties, and robust chemical stability, pristine CFs typically suffer from poor impedance matching and a single dielectric loss mechanism, resulting in weak microwave absorption (MA) within the low-frequency range of 2–8 GHz. In this work, Fe-MXene Decorated Carbon Fibers (FMCF) were fabricated by first assembling small Fe nanoparticles onto MXene via electrostatic self-assembly, followed by electrospinning and high-temperature annealing. Experimental results reveal that at a Fe-to-MXene molar ratio of 1:1, FMCF-1 achieves a low-frequency effective absorption bandwidth (EAB) of 2.35 GHz at 4 mm. Additionally, within the medium-to-high-frequency region of 8–18 GHz, it delivers a EABmax of 6.32 GHz at 2 mm. The exceptional absorption performance arises from the abundant multi-dimensional heterointerfaces formed between Fe-MXene and the carbon fiber matrix, which synergistically enhance dielectric and magnetic losses and optimize impedance matching. This work provides practical guidance for developing high-performance broadband carbon fiber-based microwave absorbing materials.