▎ 摘　　要

Thermally conductive polymeric composites are highly promising in current energy devices such as light-emitting diodes, integrated circuits, and solar cells to achieve appropriate thermal management. However, the introduction of traditional thermoconductive fillers into a polymer usually results in low thermal conductivity enhancement. Here, an ideal dielectric epoxy nanocomposite with ultrahigh thermal conductivity is successfully fabricated using three-dimensional interconnected boron nitride nanotube reinforced graphene oxide nanosheet (3D-BNNT-GONS) aerogels as fillers. The nanocomposite exhibits a nearly 20-fold increase in thermal conductivity with only 11.6 vol % loading fraction. Meanwhile, the nanocomposite possesses excellent insulation performance, including low dielectric constant, low dielectric loss, and high breakdown strength. A heating and cooling process reveals that the nanocomposite has a fast response of surface temperature, indicating high thermal management capability.