Hetero-folded hBN/graphene with ultrahigh thermal conduction and electrical insulation for reliable thermal management

Thermal interface materials with high out-of-plane thermal conductivity (κ_⊥) and electrical insulating properties are of great importance and urgent demand for effective and reliable thermal management of electronic devices. Resolving the tradeoff between thermal conduction and electrical insulation in thermal interface materials is still very challenging due to the typically coupled phonon and electron transport mechanism. Herein, we report a hetero-folded design and synthesis of hexagonal boron nitride/defect-free graphene with ultrahigh κ_⊥ and enhanced electrical insulating properties. The resulting material features an ultrahigh κ_⊥ up to 402 W m⁻¹ K⁻¹ by converting the in-plane thermal conductivity of graphene to κ_⊥ and enhanced surface resistivity up to 0.1 MΩ sq.⁻¹ by heterojunction assembling of hBN nanolayers. This unique combination of thermal conduction and electrical insulation endows thermal interface materials with exceptional efficiency and reliability for high-performance thermal management of electronic devices.