3D graphene and boron nitride structures for nanocomposites with tailored thermal conductivities: Recent advances and perspectives

Various three-dimensional (3D) structures are rationally assembled from two-dimensional (2D) nanosheets of graphene and boron nitride (BN) for thermal energy regulating applications. The nanocomposites containing these 3D architectures offer thermal conductivities spanning a few orders of magnitude from ultralow values for super thermal insulation to high values for fast heat dissipation. In this review, we summarize the approaches developed to achieve two extremes of thermal conductivity in 3D graphene and BN assemblies by engineering their structures at different length scales. A special focus is placed on identifying key structural parameters affecting the thermal conductivities, including pore morphologies, pore sizes, and cell wall structures. Distinctive applications of 3D graphene and BN structures and their polymer-based composites for thermal energy management are highlighted along with their potential multifunctionalities other than thermal conduction or insulation. The in-depth understanding of thermal transport properties offer insight into designing novel 3D structures that possess desired thermal conductivities for emerging thermal management applications.