Cactus-like double-oriented magnetic SiC and BN networks leading to simultaneously enhanced dielectric strength and thermal conductivity of epoxy composites

Epoxy-based composites with high insulation and thermal conductivity are desirable materials for electronic and electrical applications. However, resolving the tradeoff between insulation and thermal conductivity remains challenging. Based on the functional requirement, we designed and fabricated a cactus-like double-oriented epoxy composite by combining magnetic orientation and ice-templated methods. Semiconducting SiC endowed the composite with field-grading characteristics, thus relieving local electric field stress along the horizontal direction, while BN with high thermal conductivity promoted heat dissipation along the vertical direction. The composite exhibited its highest performance with 15 vol% filler, improving the breakdown voltage and thermal conductivity by 43.7% and 1312% compared with pure epoxy, respectively, outperforming recently developed packaging materials. It is believed that this work offers an efficient strategy for the fabrication of the filler structure and provides insights on the simultaneous enhancement in insulation and thermal conductivity of polymer composites .