3D Interconnected Boron Nitride Macrostructures and Derived Composites for Thermal Energy Regulation

Abstract Among the diverse categories of 2D materials, hexagonal boron nitride (BN) has emerged as a preeminent contender due to its exceptional mechanical, chemical, and thermal attributes. The construction of 3D interconnected network macrostructures (3D‐IBNM) from 2D BN building blocks represents a pivotal advancement, yielding next‐generation materials with preserved surface area (2078 m²g⁻¹) and 99.99% porosity. Exploiting such high porosity in interconnected BN structures holds promise for achieving ultralow thermal conductivity (k) and enhancing the k of compounded matrices through synergistic effects. In recent years, considerable attention has been directed toward developing extreme k materials based on BN macrostructures, with implications spanning from superinsulation to conduction. This review endeavors to present the latest advancements in 3D‐IBNM, commencing with a succinct overview of 2D BN and the merits of its 3D interconnected configurations. Subsequently, it delves into state‐of‐the‐art fabrication strategies encompassing free‐standing BN macrostructures and in situ composites. The review then elucidates the diverse applications of 3D‐IBNM and their derived composites within the realm of thermal energy, encompassing areas such as transfer, storage, conversion, and insulation. Last, it outlines prospective directions and future avenues for designing 3D‐IBNM geared toward achieving extreme k.