Anisotropic MoS2/SiC Aerogels: A Multifunctional Platform for Broadband Electromagnetic Stealth and Thermal Management

en This link goes to a English section zh This link goes to a Chinese section To address the demand for high-temperature stability, broadband strong absorption, and multifunctional integration of electromagnetic wave absorbing materials in complex service environments, lightweight molybdenum disulfide (MoS 2 ) decorated silicon carbide (SiC) nanofiber composite aerogels with a directional layered interconnected structure were successfully fabricated in this study via a hydrothermal method combined with directional freeze casting and thermal annealing processes. Microstructurally, the aerogel exhibits a “shish-kebab-like” heterostructure formed by MoS 2 nanosheets uniformly wrapping SiC nanofibers. Furthermore, the heat treatment process regulated the phase transformation of MoS 2 from the 1T phase to the 2H phase, retaining abundant defect sites. Benefiting from the significant anisotropy induced by the directional pore structure, the material demonstrates optimal impedance matching characteristics and dielectric loss capability when electromagnetic waves are incident parallel to the directional structure. The optimized MoS 2 @SiC-2 sample not only possesses an ultralight density (0.157 g cm −3 ) but also achieves superior microwave absorption performance in the X-band: a minimum reflection loss (RL min ) of −34.56 dB and an effective absorption bandwidth (EAB) covering the entire X-band (4.2 GHz). In addition, this unique three-dimensional directional lamellar structure endows the material with excellent thermal insulation performance, exhibiting a thermal conductivity as low as 0.057 W m −1 K −1 in the direction perpendicular to the directional structure, along with outstanding fire resistance and thermal shock resistance. Integrating high-efficiency electromagnetic stealth and thermal protection functions, this MoS 2 @SiC aerogel provides a novel design strategy for electromagnetic protection applications in harsh environments. 摘要(Chinese ): en This link goes to a English section zh This link goes to a Chinese section 针对复杂服役环境下对电磁波吸收材料高温稳定性、宽频强吸收及多功能集成的需求,本研究通过水热法结合定向冷冻铸造与热退火工艺,成功制备了具有定向层状互联结构的轻质二硫化钼(MoS 2 )负载碳化硅(SiC)纳米纤维复合气凝胶。该气凝胶在微观上呈现出由MoS 2 纳米片均匀包裹SiC纳米纤维形成的“糖葫芦”状异质结构,且热处理过程调控了MoS 2 从1T相向2H相的转变,保留了丰富的缺陷位点。得益于定向孔隙结构引发的显著各向异性,当电磁波平行于定向结构入射时,材料展现出最佳的阻抗匹配特性和介电损耗能力。优化后的MoS 2 @SiC-2样品不仅具有超轻密度(0.157 g cm −3 ),更在 X 波段实现了卓越的吸波性能:最小反射损耗(RL min )达到-34.56 dB,且有效吸收频宽(EAB)覆盖了整个 X 波段(4.2 GHz)。此外,独特的三维定向层板结构赋予了材料优异的隔热性能,垂直于定向结构方向的热导率低至 0.057 W m −1 K −1 ,并表现出出色的耐火性和抗热冲击性。这种集高效电磁隐身与热防护功能于一体的 MoS 2 @SiC气凝胶,为恶劣环境下的电磁防护应用提供了新的设计思路。