Lightweight, high-temperature-resistant carbon-bonded carbon fiber (CBCF) composites with excellent thermal insulation properties are desirable materials for thermal protection systems in military and aerospace applications. Here, glucose was introduced into the polyacrylamide hydrogel to form the glucose-polyacrylamide (Glu-PAM) hydrogel. The CBCF composites were prepared using the Glu-PAM hydrogel as a brand-new binder, and the synergistic effect between glucose and acrylamide was investigated. The results showed the Glu-PAM hydrogel could limit the foaming of glucose and enhance the carbon yield of glucose. Meanwhile, the dopamine-modified chopped carbon fiber could be uniformly mixed by high-speed shearing to form a slurry with the Glu-PAM hydrogel. Finally, the slurry was successfully extruded and molded to prepare CBCF composites with a density of 0.158~0.390 g cm⁻³ and excellent thermal insulation performance and good mechanical properties. The compressive strength of CBCF composites with a density of 0.158 g cm⁻³ in the Z direction is 0.18 MPa, and the thermal conductivity in the Z direction at 25 °C and 1200 °C is 0.10 W m⁻¹ k⁻¹ and 0.20 W m⁻¹ k⁻¹, respectively. This study provided an efficient, environment-friendly, and cost-effective strategy for the preparation of CBCF composites.

Lithium–sulfur (Li-S) batteries, due to their high theoretical capacity, intrinsic overcharge protection, and low cost, are considered as the most promising candidates for next-generation energy storage systems. To promote widespread use of Li-S batteries, various tactics have been reported to improve the columbic efficiency and to suppress the shuttle effect. Herein, we report a novel polymeric sulfur via heat radical polymerization, for the Li-S battery. The insolubles after CS₂ washing, and the changes in XRD (X-ray diffraction) results imply the formation of polymeric sulfur. Owing to the absence of cyclic S₈ molecular, the shuttle effect is depressed, and the polymeric sulfur cathodes exhibit lower self-discharge rates, higher sulfur utilization, better rates of performance, and enhanced cycling stabilities than the commercial sublimed sulfur. Thus, polymeric sulfur provides a new train of thought and tactics for restricting the formation of the dissolution of polysulfides, and self-discharge.

The boron carbide (B₄C) nanoparticles doping mesophase pitch (MP) was synthesized by the in-situ doping method with tetrahydrofuran solvent, and the corresponding MP−based carbon fibers (CFs) were successfully prepared through the melt−spinning, stabilization, carbonization and graphitization processes. The structural evolution and properties of boron−containing pitches and fibers in different processes were investigated for exploring the effect of B₄C on mechanical, electrical and thermal properties of CFs. The results showed that the B₄C was evenly dispersed in pitch fibers to provide active sites of oxygen, resulting in a homogeneous stabilization and ameliorating the split−ting microstructures of CFs. Moreover, the thermal conductivity of B1−MP−CF prepared with 1 wt.% B₄C increased to 1051 W/m•K, which was much higher than that of B0−MP−CF prepared without B₄C (659 W/m•K). While the tensile strength of B₄C−doped CFs was lower than that of pristine CFs. In addition, a linear relationship equation between the graphite microcrystallite parameter (I_D/I_G) calculated from Raman spectra and the thermal conductivity (λ) calculated according to the electrical resistivity was found, which was beneficial to understand the thermal properties of CFs. Therefore, the doping B₄C nanoparticles in MP did play a significant role in reducing the graphitization temperatures due to the boron catalytic graphitization but decreasing the mechanical properties due to the introduction of impurities.

This study systematically investigated the diffusion bonding of SiC ceramics using Ti interlayers via spark plasma sintering. The effects of holding time (5 min, 10 min, 20 min), joining temperature (1300 °C, 1400 °C, 1500 °C), and Ti foil thickness (5 μm, 10 μm, 20 μm) on joint microstructure and shear strength were characterized through SEM, TEM, XRD, and EDS. The results revealed that the joining temperature was the key factor influencing joint performance, while the holding time and Ti foil thickness had relatively minor effects. When joined at 1300 °C, the primary reaction products in the interlayer consisted of TSC, TiC, and Ti₅Si₃ phases. Prolonged holding times improved the shear strength, but inhomogeneous phase distribution adversely affected the stability of mechanical properties. In joints with thinner Ti interlayers (5 μm and 10 μm), Si-rich phases tend to aggregate in the central region, leading to stress concentration and reduced joint strength. As the joining temperature increased to 1400 °C and 1500 °C, the Ti₅Si₃ phase was gradually consumed, and the interlayer primarily contained TSC and TiC phases, leading to a significant enhancement in shear strength, with a maximum value of 127.67 MPa achieved at 1400 °C. These findings provide important experimental evidence and theoretical support for optimizing the joining process of SiC ceramics.