N-doped FeCoNi/MoS2@cnts/cnfs aerogels with magnetic-dielectric synergy for heat insulation, infrared stealth, and electromagnetic wave absorption

Abstract

To develop multi-functional microwave-absorbing materials, the FeCoNi/MoS₂@carbon nanotubes (CNTs)/carbon nanofibers (CNFs) aerogels were synthesized by anchoring FeCoNi and MoS₂ onto an aerogel skeleton via directional freeze-drying and catalytic chemical vapor deposition (CCVD). Through CCVD, a diverse array of heterointerfaces was successfully constructed and defect-containing CNTs were introduced, thereby improving the impedance mismatch of carbon-based aerogels while achieving outstanding microwave absorption performance. The composite aerogel results in a minimum reflection loss of −84.18 dB at the thickness of 1.85 mm and an effective absorption bandwidth of 5.40 GHz at the thickness of 1.75 mm with a 13 % filler ratio. The excellent electromagnetic wave absorbing ability is mainly ascribed to the formation of three-dimensional conduction network, abundant heterogeneous interfaces, and the introduction of magnetic loss. Density functional theory calculations further elucidate that the enhanced dielectric properties arise from asymmetric charge distribution at heterogeneous interfaces (FeCoNi–C and MoS₂–C), which amplifies interfacial polarization, while the increased density of states optimizes conduction loss. Additionally, the composite aerogels exhibit exceptional thermal insulation and infrared stealth performance. This work pioneers a novel pathway method for multifunctional aerogels using CCVD.