Single-source-precursor derived SiOC ceramics with in-situ formed CNTs and core–shell structured CoSi@C nanoparticles towards excellent electromagnetic wave absorption properties

In this work, novel carbon nanotube (CNT)/CoSi/SiOC nanocomposite ceramics with in-situ formed multi-walled CNTs and core-shell structured CoSi@C nanoparticles were successfully prepared via a single-source-precursor derived ceramic approach.Ppolymeric precursor characterization as well as phase evolution, microstructure, and electromagnetic wave (EMW) absorption properties of the ceramics were investigated in detail.The results show that the in-situ formed CNTs and magnetic CoSi@C nanoparticles provide a synergistic effect on both dielectric loss (tanδ ε ) and magnetic loss, leading to outstanding EMW absorption properties of the ceramics annealed at only 1100 ℃. (i) For the Co feeding of 6.25 wt%, the minimum reflection loss (RL min ) is -53.1 dB, and the effective absorption bandwidth (EAB) is 4.96 GHz (7.12-12.08GHz) with a ceramic-paraffin hybrid sample thickness of 3.10 mm, achieving full X-band coverage; (ii) for the Co feeding of 9.09 wt%, the RL min value of -66.4 dB and the EAB value of 3.04 were achieved with a thickness of only 2.27 mm.Therefore, the present CNT/CoSi/SiOC nanocomposite ceramics have potential applications for thin, lightweight, and efficient EMW absorption in harsh environments.