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.

Design and optimization of electrode material structures are critical steps in the development of supercapacitors. This work presented a design strategy based on SiC nanowires (NWs) as supercapacitor electrode with gradient pore structure, superhydrophilicity, and enhanced conductivity. SiCNWs were in-situ fabricated on a carbon fabric substrate radially via chemical vapor deposition (CVD), constructing conical channels with gradient pore sizes that generate capillary forces and promote ion transport. An ultrathin pyrolytic carbon (PyC) shell (4.98 nm) was coated on the SiCNWs, to improve electrical conductivity without compromising pore structure or wettability. SiCNWs@PyC electrodes with a diameter of ~0.93 μm exhibited excellent electrochemical performance from 0 to 60 ℃. At 25 ℃ and a current density of 0.2 mA/cm², the areal capacitance of SiCNWs@PyC electrode was 32.48 mF/cm², representing 227.58% of the areal specific capacitance of pure SiCNWs. At 60 ℃, the capacitance remained high at 28.09 mF/cm² under the same current density. The in-situ growth strategy and high mechanical stability of the material enabled the symmetric supercapacitor to maintain outstanding rate performance and cycling stability across a wide temperature range. The SiCNWs@PyC core-shell nanostructure is a promising supercapacitor electrode material, offering valuable insights for the development of next-generation energy storage devices.

For the inadequate interlaminar strength of 2D carbon/carbon (C/C) composite, in-situ grown carbon nanotubes (CNTs) reinforcing strategy was put forward to strengthen the interlaminar matrix at the nanoscale and inhibit the interlaminar cracking. CNT morphology is an essential factor in influencing the enhancement effect. Herein, the influence of in-situ grown CNT morphology on the microstructure and mechanical properties of C/C composite was deeply studied. The radially-aligned straight CNTs could induce the formation of highly-ordered pyrolytic carbon (PyC), while PyC in randomly-distributed curved CNTs concentrated area exhibits an isotropic structure. Further, radially-aligned straight CNTs show better improvement on the flexural and shear strength of C/C composites. According to the fine structural characterization and finite element simulation, the influence mechanism of CNT morphology was revealed. CNT morphology can influence the stress distribution in the PyC protective layer, and compared with radially-aligned straight CNTs, randomly-distributed curved CNTs induce higher tensile stress in the PyC protective layer, which has a detrimental impact on the flexural and shear properties of C/C composite. This work provides novel insights into the effect of CNT morphology on the microstructure and mechanical properties of C/C composites, which gives a basis for the structural design and preparation of CNTs reinforced C/C composites.