Controllable preparation of graphene glass fiber fabric towards mass production and its application in self-adaptive thermal management

Conformal hexagonal boron nitride encapsulation of graphene-skinned glass fiber fabric for enhanced electrical stability

Encapsulation is crucial for protecting graphene devices, but traditional whole-package encapsulations usually add bulky structures and reduce their flexibility. Hexagonal boron nitride (h-BN) holds potential for graphene encapsulation, but faces challenges in large-area acquisition and conformal coverage due to limitations in exfoliation and transfer techniques. Graphene-skinned glass fiber fabric (GGFF), made via graphene CVD growth on each fiber of a glass fiber fabric, consists of a hierarchical conductive network, but pressure/deformation-induced inter-fiber contact resistance fluctuations destabilize its electrical conduction. Whole-package encapsulation cannot resolve this, as fails to insulate inter-fiber contacts. Herein, thick, high-quality h-BN films are CVD-grown on each fiber in GGFF, achieving conformal encapsulation. This unlocks conductive network in GGFF, stabilizing electrical conduction while preserving structure stability and flexibility. This also improves GGFF's resistance to doping and oxidation, extending its service life. This encapsulation strategy is broadly applicable to other two-dimensional materials and complex device structures, promoting reliable nanoelectronics in demanding environments.

Core-shell structured BN/SiO2 nanofiber membrane featuring with dual-effect thermal management and flame retardancy for extreme space thermal protection

With the rapid progress of aerospace frontier engineering, the extreme space thermal environment has brought severe challenges to astronauts' space suits, putting forward higher requirements for thermal protection materials. On this basis, a unique core-shell structured hexagonal boron nitride (h-BN)/silicon dioxide (SiO2) nanofiber membrane (HS) was prepared using the coaxial electrospinning method, of which both the thermal insulation SiO2 nanofiber cortex and the passive radiation cooling (PRC) h-BN nanofiber core make it a promising dual-effect thermal management material. Especially, when the amount of h-BN is 0.9 g, the resultant HS (HS0.9) exhibits astonishing low thermal conductivity of 0.026 W m-1 K-1 and high reflectivity and emissivity of exceeding 90% over an extremely wide range. The expected dual-effect thermal management performance enables the HS to have an ideal cooling effect under both high sunlight intensity and strong light radiation. In addition, HS also shows excellent flame retardant performance arising from the excellent high-temperature stability of h-BN and SiO2. What is more, the tensile strength of HS0.9 was also significantly increased from 0.42 to 7.2 MPa by encapsulating polyimide through vacuum filtration. Therefore, the research results of this work provide innovative highlights for high-temperature protection in daily life and even extreme space environments.