Synthesis of PAN/ZIF-67 derived composite fibers through electrospinning technology with superior Ku-band electromagnetic absorption performance

Abstract

With the rapid development of 5G technology, electromagnetic pollution has emerged as a critical concern. Composite nanofibers prepared by electrospinning technology have the advantages of low density, high flexibility and easy processing, and are important materials for electromagnetic wave (EMW) absorption. In this work, cubic zeolitic imidazolate framework-67 (ZIF-67) was uniformly incorporated into carbon nanofibers (CNFs) through electrospinning, and then carbon nanofibers/cobalt (II) oxide/cobalt/nitrogen-doped carbon (CNFs/CoO/Co/NC) composite fibers were prepared by calcination at different temperatures. The magnetic carbon composites derived from cubic ZIF-67 were integrated with CNFs to form bamboo-like composite fibers. The unique microstructure and reasonable selection of calcination temperature provided channels for energy and charge transfer, increasing the multiple scattering of waves within the composite fibers. When the calcination temperature was 800 °C, the CNFs/CoO/Co/NC composite fibers exhibited the minimum reflection loss of −63.71 dB at a matching thickness of 2.56 mm and the broadest effective absorption bandwidth of 7.92 GHz at 3.2 mm and a low filling ratio of 10 wt%. Furthermore, the obtained composite fiber presented the best radar cross section (RCS) reduction performance, reaching the maximum value of −52.37 dB m². Additionally, the potential EMW dissipation mechanism was also revealed. Therefore, this work provided a new strategy for producing CNFs-based composites through electrospinning as broadband and highly efficient EMW absorbers.