Hexagonal boron nitride nanosheets: Preparation, heat transport property and application as thermally conductive fillers

The urgent need for ultrahigh thermally conductive materials to keep up with the rapid development of the electronics industry has led to the exploration of hexagonal boron nitride nanosheets (BNNSs) as an ideal material for thermal transport/dissipation applications. BNNSs possess outstanding mechanical strength, electrical insulation, thermal conductivity, and low density, as well as remarkable oxidation resistance. This article provides a comprehensive review of various fabrication methods for BNNSs and compares their advantages and disadvantages. Additionally, the article discusses the impact of several BNNS properties, including thickness, size, interface, isotopic concentration, and defects, on their thermally conductive properties. Lastly, the review delves into the use of BNNSs as highly thermally conductive fillers in polymer-based materials, highlighting the significant effects of the content, directionality, dispersibility, and structure of BNNSs within the polymer matrix on the composite's thermally conductive properties. This review aims to spark new fabrication methods and improvements to achieve BNNS/polymer composites and promote their practical application as thermal transport/dissipation materials.