FeCo Nanoparticles Embedded in Carbon Microfibers Derived from Conjugated Microporous Polymers for Enhanced Electromagnetic Wave Absorption

Significant progress has been made in developing multicomponent carbon-based fibers. However, challenges remain in accurately controlling their composition and microstructure to achieve lightweight fiber materials with high absorption and a broad frequency bandwidth. Herein, we report a microwave-absorbing FeCo/C fiber derived from conjugated microporous polymers (CMPs) by electrospinning and carbonization. The incorporation of CMP-derived carbon not only promotes the uniform dispersion of FeCo nanoparticles and conductive network formation, but also enhances the polarization loss within the microfiber’s carbon skeleton. The multicomponent design strategy promotes impedance matching, where FeCo nanoparticles provide substantial magnetic loss while the carbon-based microfibers establish long-distance conductive channels with enhanced polarization loss and multiple reflections. Consequently, the optimized FeCo/C fiber exhibits excellent microwave absorption performance, with a minimum reflection loss of −59.9 dB and an effective absorption bandwidth of 5.1 GHz (thickness: 2.5 mm). This work will inspire the development of lightweight multicomponent fiber materials with optimized impedance matching and multiple loss mechanisms, and show promising prospects in absorbing stealth applications.