From material design to structural optimization : Genetic algorithm-driven magnetic carbon fiber aerogels for broadband microwave absorption

Abstract

Carbon fiber (CF) is widely used in civil and military fields due to its exceptional physicochemical properties, surpassing other engineering materials. However, its high conductivity can cause impedance mismatching, limiting its effectiveness in microwave absorption. To develop a high-performance CF-based microwave absorber with a broad effective absorption bandwidth (EAB), this study combines material and macro-structural design. Magnetic CoFe2O4-coated chopped carbon fiber (SCF) is synthesized at the laboratory scale using a straightforward acid-oxidation and chemical co-precipitation method to enhance impedance matching. The resulting magnetic SCF aerogels, constructed with cellulose nanofibers as a dispersant and crosslinking agent through random freezing and freeze-drying, exhibit improved microwave absorption, achieving optimal absorption intensity of −52.3 dB and a maximum EAB of 5.5 GHz. By further optimizing honeycomb structure dimensions and selecting ideal magnetic SCF aerogels via a genetic algorithm, a highly effective absorber structure is realized, delivering an ultra-wide EAB of approximately 14 GHz with a thickness of 9.7 mm. This integration of magnetic SCF aerogels with periodic structural design offers a promising direction for the development of advanced microwave absorption materials, particularly for use in honeycomb sandwich structures in stealth fighter wings and fuselages.