Three-Dimensional Boron Nitride Networks in Polymer Composites: Fabrication Strategies and Thermal-Management Applications

Abstract

Boron nitride nanosheets (BNNSs) combine high intrinsic thermal conductivity, electrical insulation, and chemical stability, making them attractive electrically insulating fillers for electronic thermal management applications. However, the random dispersion of BNNSs within polymer matrices severely restricts the effective construction of thermally conductive pathways, resulting in limited thermal conductivity of the resultant composites. A central challenge is to construct continuous thermally conductive networks at relatively low BN loadings while reducing interfacial thermal resistance. To address this issue, this review first introduces two mainstream solutions: multi-dimensional filler hybridization and the construction of three-dimensional (3D) boron nitride (BN) networks. This review focuses on representative strategies for engineering BN-based thermal architectures, including external-field-driven alignment, template-assisted assembly, and geometry-guided structural design, with particular emphasis on the transition from directional alignment to multidirectionally interconnected 3D networks. It elucidates the structure–property relationships governing interfacial thermal resistance modulation and phonon transport enhancement. Furthermore, this review summarizes the recent advances in applications of 3D BN networks in electronic thermal management, phase-change energy storage, and radiative cooling, while also discussing key challenges related to scalability, durability, multifunctional integration, and adaptability to complex operating conditions. Finally, future research directions are discussed, highlighting smart-responsive thermal management materials, multiphysics-coupled design, and data-driven structural optimization, aiming to provide a theoretical foundation and technical guidance for the design and engineering application of next-generation high-performance polymeric thermal management materials.