▎ 摘　　要

The thermally conductive properties of polymer composites are hugely constrained by discontinuous filler networks and high thermal contact resistances in filler/filler interfaces. Herein, a silver nanoparticle-decorated boron nitride hybrid (BN@AgNPs) is fabricated via in situ reduction of Ag+. Subsequently, the AgNP-enhanced three-dimensional BN/reduced graphene oxide (3D-BN/rGO) skeleton with continuous structures possessing "point-plane" connections is prepared via hydrothermally treating the aqueous slurry containing BN@AgNPs and GO followed by freeze-drying. It is established that rGO serves as a scaffold to assemble BN@AgNPs into 3D structures. Notably, the AgNP-enhanced 3D-BN/rGO skeleton makes the polydimethylsiloxane (PDMS) composite exhibit a high thermal conductivity of 2.34 W w(-1) K-1 at a low filler loading of 23.8 wt %, which is 41.8 and 207.9% higher than that of the PDMS composite incorporated with the original 3D-BN/rGO skeleton and BN flakes at the same loading, respectively. Meanwhile, the composite also exhibits a high volume resistance of 6.9 X 10(13) Omega cm(-1). Thermal resistance analysis demonstrates that assembling BN flakes into 3D skeletons makes phonon transfer along BN flakes rather than BN/PDMS interfaces with larger resistances, and the introduction of AgNPs depresses the phonon scattering in BN/BN interfaces. Finite element simulation further reveals that the AgNPs on BN planes and BN edges elevate the heat transfer in BN planes and BN/BN interfaces, respectively. Our work provides a promising approach for fabricating thermally conductive and electrically insulating polymer composites utilized in electronics.