Carbon Nanotubes Grown In Situ on Si ₃ N ₄ Whiskers for Efficient Thermal Conductive Composites

Order‐aligned structures of thermally conductive fillers in the matrix are of great importance for the highly effective thermal interface materials (TIMs) in the fields of electronic devices, semiconductors, and electronic packaging. However, achieving high thermal conductivity via constructing ordered structures with low filler content remains challenging. Here, we construct vertically aligned Silicon nitride (Si 3 N 4 ) whiskers covered by the in situ growth of carbon nanotubes (CNTs) to form an efficient thermal conductive network. Owing to the successful construction of interconnected structures via thermally conductive Si 3 N 4 whiskers and CNTs, the Si 3 N 4 @CNTs/EP composite with filler content of 8.31 vol% exhibits high out‐of‐plane thermal conductivity of 1.54 W m −1 K −1 and excellent electrical insulation. This finding provides a promising strategy to design high‐performance thermal conductive composites for TIMs in high‐power devices.