Enhanced through-plane thermal conductivity in Polymer nanocomposites by constructing graphene-supported BN nanotubes

Abstract

Although graphene-related nanocomposites have great potential for dissipating excess heat to ensure that electronic devices have high efficiencies and long service lives, their practical applications are restricted by the ultra-low through-plane thermal conductivity of these composites, which is due to interfacial thermal resistance between the graphene layers. Herein, exfoliated graphene (E-G)-boron nitride nanotube (E-G–BNNT) hierarchical structures are developed via the in situ growth of BNNTs on E-G. The BNNTs play an essential role in the construction of vertically aligned “bridges” for connecting E-G nanosheets during the hot-pressing process, while covalent C–N bonding at the E-G and BNNT interface creates a heat transfer pathway between graphene layers to reduce interfacial thermal resistance. The resultant E-G–BNNT composite has an architecture that is close to an ideal thermal conductive filler, and it is highly efficient at improving the through-plane thermal conductivity of PDVF-based nanocomposites, reaching 3.12 W m⁻¹ K⁻¹ at a loading of 15 wt%. Non-equilibrium molecular dynamics (NEMD) simulations further show that the development of covalent C–N bonding between E-G and BNNTs can effectively boost the interfacial thermal conductivity. Such excellent heat conduction performance allows the nanocomposite to show great potential for thermal management.