Chitosan-intercalated rectorite/biomass carbon aerogels with enhanced heterogeneous interfaces for broadband microwave absorption

Narrow-band absorption caused by insufficient heterogenic interfaces in biomass-derived carbon materials has significantly impeded their advanced applications in microwave absorption field. Herein, we introduce composite porous carbon aerogels, meticulously crafted by integrating natural silicate clay rectorite (REC) lamellae with chitin/chitosan (CT/CS) biomass carbon. The lamellae are intercalated with chitosan and assembled onto the surface of regenerated chitin fibers. Upon carbonization, the lamellae and chitin/chitosan-derived bio‑carbon form an oriented hierarchical cellular architecture with numerous heterogeneous interfaces. This innovative design modulates the dielectric characteristics, fine-tuning impedance matching and significantly enhancing absorption performance. Consequently, the composite aerogel, with a thickness of only 3.5 mm, achieves an unprecedented broadband microwave absorption bandwidth of 8.3 GHz (9.7–18 GHz, X-Ku band). This remarkable bandwidth extends to 58% of the X band and encompasses the entire Ku band, surpassing the capabilities of most microwave absorbing materials (MAMs) reported. Radar cross-section simulations confirm that carbonized REC/CT/CS (cRTS) can significantly diminish radar reflection signals (44 dBsm at 90°), highlighting its potential as a state-of-the-art radar stealth material. This pioneering work establishes a new paradigm in the development of MAMs, demonstrating the potential of sustainable biomass and low-cost clay in constructing microwave adsorbents with ultra-broadband absorption capabilities.