Nanocellulose-polysilazane single-source-precursor derived defect-rich carbon nanofibers/SiCN nanocomposites with excellent electromagnetic absorption performance

Ceramic SiCN nanocomposites modified with nanocellulose derived defect-rich carbon nanofibers (CNFsSiCN) were developed by thermolysis of nanocelulose-polysilazane single-source precursors (SSPs). Multi-loss mechanisms (i.g. polarization loss and conductive loss) were established in the SiCN ceramic nanocomposites by employing the defect-rich structure of CNFs. Cole-Cole circle plots indicate that the CNFs-SiCN ceramics possess strong polarization capability due to the defect-rich structure of the CNFs. Dielectric loss values fitted by the Debye theory showed that the proportion of polarization loss reaches an unprecedented high value, accounting for 52.1% of the total dielectric loss. When the content of nanocellulose is 10 wt% of SSPs, the minimal reflection coefficient (RCmin) and effective absorption bandwidth (EABs) of CNFs-SiCN ceramic can reach -36.3 dB and 3.0 GHz, respectively. This work may contribute new ideas for establishing multi-loss mechanisms in ceramic-based materials, finding a new application for nanocellulose, and shaping the design of novel absorbents. (c) 2021 Elsevier Ltd. All rights reserved.