Net-like SiC@C coaxial nanocable towards superior lightweight and broadband microwave absorber

In this study, a practical lightweight and broadband microwave absorber, namely, the net-like amorphous carbon-coated silicon carbide coaxial nanocables (SiC@C NCs), which had low density and excellent physicochemical stability, was successfully fabricated according to the hydrothermal-carbonization strategy. Typically, the microwave absorption performance exhibited broad effective absorption bandwidth (EAB) of up to 7.2 GHz (9.12–16.32 GHz) at a small matching thickness of 2.58 mm. Meanwhile, the minimal reflection loss (RL) value of −51.53 dB with the corresponding EAB across the whole Ku-band (11.68–18 GHz) appeared at 2.08 mm, which suggested that, the as-prepared SiC@C NCs displayed extensive application prospects as a superior lightweight and broadband microwave absorber. Moreover, the systematic characterization results indicated that, the superior microwave absorption performance was ascribed to the interfacial polarization and multiple reflections on the heterogeneous interface between the SiC nanowires (SiC NWs) core and the amorphous carbon shell, together with the electron polarization and Debye dipolar relaxation resulted from the stacking faults of SiC NWs core, and the abundant defect and disorder within the amorphous carbon shell.