Phase change thermally conductive composites with highly vertically oriented boron nitride

In recent years, with the upgrading and iteration of semiconductor technology and the popularization of 5G and AI, electronic devices have exhibited trends of lightweight, miniaturized and high power. Conventional thermal management materials have demonstrated limitations in terms of insulation and thermal conductivity. Therefore, there is an urgent need to explore and develop novel thermal interface materials (TIMs) featuring high thermal conductivity and excellent insulation properties. In this study, a series of composites with randomly distributed hexagonal boron nitride (h-BN) were fabricated via high-temperature blending. After selecting the sample with the highest thermal conductivity (R-50BN), rolling and hot-pressing processes were employed to achieve vertical orientation of h-BN, forming oriented thermal conduction units (O-50BN). Within this composite system, paraffin wax (PW) was blended with ethylene-vinyl acetate (EVA) and synergistically interconnected with h-BN, thereby establishing a continuous three-dimensional thermal conduction network.O-50BN exhibits an outstanding through-plane thermal conductivity of up to 7.88 W m −1 K −1 and a phase change latent heat of 60.13 J g −1 . It also possesses excellent insulation properties, with a dielectric constant of 3.1 at 25 °C and 10 6 Hz and a volume resistivity of 10 14 Ω cm at room temperature, while maintaining remarkable thermal stability and reliable cycling performance. Practical application tests demonstrate that O-50BN significantly reduces the operating temperature of high-power LED lamps, presenting promising prospects for engineering applications. This work provides an effective material solution for addressing thermal management challenges in high-power electronic devices.