Recent advances in thermal properties of graphene/hexagonal boron nitride heterostructures and their polymer nanocomposites: A review

Efficient thermal management has become increasingly crucial for modern electronic devices, driven by unstoppable trends toward miniaturization, higher power densities and multifunctional integration. Effective thermal interface materials (TIMs) are essential for mitigating heat accumulation and ensuring reliable device performance and long lifespan. Graphene and hexagonal boron nitride (h-BN) have attracted tremendous attention as high-performance nanofillers in polymer composites due to their exceptionally high thermal conductivity (TC) and mechanical strength. Recent research has increasingly focused on polymer nanocomposites reinforced by graphene/h-BN (Gr/h-BN) heterostructures, highlighting significant synergistic improvements in their thermal and mechanical properties. These heterostructures synergistically combine the exceptional TC and mechanical strength of graphene with the outstanding electrical insulation and thermal stability of h-BN. This review comprehensively analyzes recent advancements in graphene, h-BN and their polymer-based nanocomposites. It delves into the influence of structural configurations, defect engineering, functionalization strategies, doping methods, isotopic modifications and mechanical strain on their thermal performance. Furthermore, it also explores several innovative strategies to improve interfacial thermal transport in polymer nanocomposites, including hybrid filler integration, surface functionalization, filler alignment and advanced manufacturing methods. It is hoped that this review can offers useful insights and practical guidelines for designing and developing next-generation materials for advanced thermal management in high-performance electronic applications.