Waste cotton fabric promotes high-entropy carbide ceramics nanowires growth to achieve high-performance electromagnetic interference shielding

One-dimentional high-entropy metal carbides have attracted significant attention for their exceptional physical and chemical properties, which endow them with great potential for applications in structural and functional fields. However, there is a lack of stable preparation methods, particularly on flexible substrates. In this study, we successfully synthesized high-entropy (Ti_0.2Zr_0.2H_f0.2Nb_0.2Ta_0.2)C (HEC) nanowires through a precursor pyrolysis method using waste cotton fabric as both a flexible substrate and a carbon source. Interestingly, the growth of the nanowires followed a catalyst-assisted vapor-liquid-solid mechanism, driven by the dissolution of metals and carbon-containing molecules originating from the polymer precursors and thermal decomposition of cotton fabric in the Fe-Ni alloy. This process involved nucleation of HEC and subsequent nanowire growth. The as-prepared HEC nanowires with diameters ranging from 0.05 to 0.1 μm were randomly distributed on carbonized cotton fiber substrate without a specific orientation, forming an interconnected multiscale conductive network. Owing to the synergistic effects including electrical conduction loss, dipolar polarization loss arising from lattice distortion in HEC, and polarization loss generated by numerous heterojunctions within the material, the prepared HEC nanowires exhibit outstanding electromagnetic interference (EMI) shielding performance in the X-band (8.2-12.4 GHz). For instance, the material achieved an EMI shielding effectiveness (SE) of 57.55 dB at a thickness of 1.35 mm. This study introduces novel perspectives and scalable approaches for the preparation, formation mechanism, and functional applications of nanostructured high-entropy ceramics.