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SiC x O y beaded carbon fibers were successfully fabricated for the first time using a facile and stable electrospinning and temperature process. The resulting fibers showcase a unique micro-nanocomposite structure, in which β-SiC beads with a silica-enriched surface are strung together with defect carbon fibers, as confirmed by XRD, XPS, and HRTEM investigation. The SiC x O y beaded carbon fibers display efficient microwave absorption performance, with a minimum reflection loss of -58.53 dB and an effective absorption bandwidth of 5.92 GHz. A modified Drude-Lorentz model was developed for SiC x O y beaded carbon fibers to reveal the double-peaked feature of the permittivity of these fibers, which is in good agreement with experimental measurements. Moreover, simulations were performed to extract polarized electric fields and microwave energy volume losses within a typical distribution of SiC x O y beaded carbon fibers. It is concluded that the dipole relaxation and hopping migration of localized electrons give a superior contribution to the overall decay of the microwave energy. This study indicates that SiC x O y beaded carbon fibers with a unique micro-nanocomposite structure hold great promise for microwave absorption applications. Additionally, this fabrication strategy offers a unique approach to producing micro-nanocomposite structures and highlights their potential applications.

Maintaining the dynamical microwave synchronization between a target and its background is the key to electromagnetical invisibility in real environment. Herein, we introduce an archetypical paradigm for ultraelastic films of graphene-functionalized ionic gel with tunable microwave-absorbing behaviors. Inspired by the local structural changes during the wing-spreading process of vespertilionids, the experimental and finite element simulations have revealed that proper shape changing of 3D wrinkled structure containing ridge walls with moderate impedance is the effective way to minimize reflected wave and promote energy attenuation. An optimal RL value of -43.6 dB and valid regulatory amplitude of 41.5 dB, covering a microwave-absorbing to shielding state, could be reached with only 0.2% weight fraction of the active ingredient RGO filler. The significant regulatory performance is attributed to the competitive effect between intrinsic dielectric attenuation of silicon nitride modified reduced graphene oxide (RGO-SiN), multiscattering of a 3D wrinkled structure, and evolution of the oriented RGO-SiN.