A core–shell carbon–ceramic fibrous aerogel derived from aramid-polysilsesquioxane for broadband electromagnetic wave absorption†

Carbon–ceramic composites demonstrate exceptional promise for microwave absorption in extreme environments. In this study, a hierarchical carbon–ceramic fibrous aerogel (CCFA) was synthesized via the pyrolysis of a bridged polysilsesquioxane coated aramid nanofiber aerogel. The resulting material features interconnected networks and a core–shell skeleton, which establish a dual-level impedance gradient. This unique architecture optimizes surface impedance matching between amorphous carbon and air, facilitating the penetration of incident electromagnetic waves into the ceramic-confined carbon aerogel. The synergistic coexistence of amorphous carbon and silicon oxycarbonitride ceramic phases enhances interfacial effects, amplifying dielectric polarization loss. Consequently, the CCFA achieves a minimum reflection loss of −55.66 dB and a wide effective absorption bandwidth of 8.24 GHz. Furthermore, the aerogel exhibits good thermal insulation and flame-retardant properties, critical for extreme-environment applications. This work presents an effective multilevel structural design and heterointerface engineering strategy for advancing carbon–ceramic composites in high-performance microwave absorption under demanding conditions.