Leaf Vein-Inspired Hierarchical Point–Line–Plane BNNT/WS2/Ag Welded Network for Efficient Heat Dissipation

Severe heat buildup within chips limits device stability and service life, and thermally conductive yet electrically insulating polymer nanocomposites become critical thermal interface materials (TIMs) for electronics cooling. The intrinsic interfacial thermal resistance (ITR) between discrete thermally conductive fillers in TIMs remains the core bottleneck limiting thermal conductivity improvement, and rationally constructing three-dimensional (3D) interconnected filler networks represents a feasible and efficient strategy to address this issue. Inspired by the natural hierarchical point–line–plane topological skeleton of a plant leaf, which realizes efficient internal matter transfer via long spicular lines, discoid planar scaffolds, and vein nodes, we design and produce a novel BNNT/WS2/Ag ternary hybrid thermally conductive network within an epoxy matrix. Specifically, high aspect ratio boron nitride nanotubes (BNNTs) act as one-dimensional linear thermal conduction skeletons mimicking leaf veins, while tungsten disulfide (WS2) nanosheets serve as two-dimensional planar heat-collecting and heat-spreading scaffolds with large specific surface areas. Notably, in situ photodeposited silver (Ag) nanoparticles function as biomimetic vein nodes between adjacent fillers. Low-temperature sintering enables these Ag nodes to tightly connect BNNT linear skeletons and WS2 planar nanosheets, effectively bridging isolated thermal conductive units, which is expected to reduce the effective thermal resistance of the composite system. This hierarchical point–line–plane structure constructs a continuous, unobstructed 3D thermal conduction highway inside the epoxy matrix. The resultant BNNT/WS2/Ag/epoxy nanocomposite exhibits excellent thermal conduction performance, with a prominent in-plane thermal conductivity of 21.5 W m−1 K−1 and a high through-plane thermal conductivity of 7.63 W m−1 K−1. Benefiting from the hierarchical topological structure and interconnected conductive network, the as-prepared nanocomposites possess outstanding heat dissipation capability and hold great promise for high-efficiency thermal management in advanced electronic devices.