Hierarchically porous and multicomponent synergistic SiC/Fe₃Si@rGO composite aerogel for electromagnetic wave absorption

SiC nanofiber aerogels are considered promising for electromagnetic wave (EMW) absorption owing to their high-temperature stability and tunable electromagnetic parameters. However, their inherently low electrical conductivity and single loss mechanism significantly restrict their absorption performance. Herein, Fe₃Si/SiC composite nanofibers were synthesized via electrospinning followed by high-temperature pyrolysis. Subsequently, a hierarchically porous SiC/Fe₃Si@rGO composite aerogel with multicomponent synergy is then constructed by combining ice templating with graphene oxide incorporation. The resulting aerogel achieved a minimum reflection loss (RL_min) of −46.68 dB at 8.84 GHz with a thickness of 3.0 mm. Moreover, within a thickness range of 1.5–5.0 mm, the material maintains RL < −10 dB across the entire 4–18 GHz frequency range. Mechanism analysis reveals that the introduced Fe₃Si phase contributes magnetic loss, while the graphene sheets form a three-dimensional conductive network, enhancing both conductive loss and interfacial polarization. Additionally, the incorporation of graphene refines and enriches the pore structure, which optimizes impedance matching and promotes multiple scattering of EMWs. This work provides a viable strategy for the design of lightweight and high-performance EMW-absorbing materials.