Polymer composites have been widely employed as electronic packaging materials, due to their low cost, flexibility, chemical stability, and high malleability, etc. However, the thermal conductivity of polymer composites becomes increasingly requirement, with the rapid growth of electronics toward miniaturization and high-power density. Conventional method to enhance the thermal conductivity of polymer is addition of high-content thermally conductive fillers, but it will deteriorate other significant properties of polymers, such as optical, electrical, and mechanical performance. Herein, we report an ice-templated assembly strategy to construct three-dimensional thermally conductive networks of BN nanosheets (BNNS) and silver nanowires (AgNWs) in epoxy resin composites. The thermal-conduction pathway can be easily built by the synergistic effects between two-dimensional BNNS and one-dimensional AgNW. Furthermore, the welding of the adjacent AgNWs through low-temperature sintering process enlarges the total contact area per unit filler volume. The resulted polymer composite thus exhibits a through-plane thermal conductivity of 1.10 Wm⁻¹K⁻¹ at only about 5.0 vol% fillers content, which is six times higher than that of the pure epoxy resin. This work shows great potential in advanced packaging materials, such as substrate materials and printed circuit board materials.

高分子复合材料由于其低成本，柔韧性，化学稳定性和高延展性等优点而被广泛用作电子包装材料。然而，随着电子器件向小型化和高功率的飞速发展，聚合物复合材料的导热性变得越来越需要密度。增强聚合物导热性的常规方法是添加高含量的导热填料，但它将破坏聚合物的其他重要性能，例如光学，电气和机械性能。在这里，我们报告了一种冰模板组装策略，以构建环氧树脂复合材料中BN纳米片（BNNS）和银纳米线（AgNWs）的三维导热网络。二维BNNS和一维AgNW之间的协同效应可以轻松地建立热传导路径。此外，通过低温烧结工艺焊接相邻的AgNWs会增大单位填充体积的总接触面积。因此，所得的聚合物复合材料表现出1.10 Wm的贯穿面热导率 在仅约5.0体积％的填料含量下，^-1 K ^-1，是纯环氧树脂的^-1 K ^-1的六倍。这项工作在先进的包装材料（例如基板材料和印刷电路板材料）中显示出巨大的潜力。