Highly thermally conductive electrically insulating composites composed of core–shell structure fiber boron nitride@titanium dioxide filler

Abstract With the increasing integration and power density of electronic and electrical equipment, highly thermally conductive insulating materials have a wide range of application scenarios. In this paper, a novel core–shell structure fiber thermal conductive filler hexagonal boron nitride@anatase titanium dioxide (h‐BN@AT) has been prepared by electrospinning technology first. The h‐BN@AT/epoxy resin (EP) thermally conductive and insulating composite was prepared by hot pressing. When the filler content was 30 wt%, the optimal thermal conductivity ( λ ) of h‐BN@AT/EP composite was 7.62 W/(m·K) (in‐plane) and 0.76 W/(m·K) (out‐of‐plane), which were 3088% and 324% higher than EP. The incorporation of high aspect ratio core–shell structural fibers significantly improves the efficiency of thermal conduction (TC) pathways formation within the composite. Moreover, the utilization of one‐dimensional (1‐D) anatase titanium dioxide fiber (ATO) and two‐dimensional (2‐D) boron nitride (h‐BN) establishes a multi‐level TC channel in EP, significantly increasing the λ of the composite. Notably, the composite retains outstanding insulation properties. The innovative core–shell structural fibers filler developed in this study provides a feasible method for producing thermal conductivity insulating materials. Highlights A new type of core–shell structure h‐BN@AT fiber filler is designed. High thermal conductivity insulating composite h‐BN@AT/EP are prepared by hot pressing. h‐BN@AT can effectively improve the thermal conductivity of composite to ensure good electrical properties. The effect of h‐BN content in h‐BN@AT filler on the properties of the composite was obtained. The superiority of h‐BN@AT in heat conduction is verified by the classical heat conduction model and simulation.