Cosmetic cotton-derived fibrous Co/C composites for highly efficient microwave absorption properties

Due to the increasing interference and pollution of electromagnetic radiation， there is an urgent need for lightweight and low-cost electromagnetic absorbing materials. In this study， carbon fiber Co/C functional composites with Co nanoparticle coatings are prepared. Among them， ZIF-67 particles are in-situ grown on the surface of cosmetic cotton， and then the lightweight Co/C precursor is prepared by direct carbonization method. The SEM image shows that the Co particles are uniformly distributed on the surface of the carbon fiber， and the uniformly distributed cobalt nanoparticles provide a magnetic coupling network and form a rich non-homogeneous interface with the carbon fiber， enhancing the interfacial polarization， and benefiting the broadband absorption behavior of the composite. The test results show that the thickness of Co/C-650 material is only 1.5 mm， the minimum reflection loss at 17.76 GHz is -42.03 dB， the effective absorption bandwidth is up to 3.68 GHz， and the radar cross section value is up to -26.8 dB·m2. This excellent electromagnetic wave absorption performance is attributed to the dielectric loss by interfacial polarization， magnetic loss by magnetic resonance， and multiple reflections and scatterings in the micro- and nano-level fiber structure. This study provides an idea for preparing ultralight， low-cost， sustainable microwave absorbers with excellent electromagnetic wave absorption capability.