Vertically Aligned Boron Nitride Fiber Paper Thermal Interface Materials with High Electrical Insulation for Electronics Heat Dissipation

Effective thermal management is critical for ensuring the reliability of modern high-power electronic devices, where thermal interface materials (TIMs) play key roles in minimizing contact resistance and improving heat dissipation. Boron nitride (BN) is widely used as a thermally conductive filler due to its high in-plane thermal conductivity and electrical insulation. However, achieving BN-based polymer composites that simultaneously offer high filler loading, flexibility, and high thermal conductivity (κ) remains a significant challenge. In this work, we introduce a novel two-step fabrication strategy to overcome this limitation. First, continuous BN fibers with high aspect ratios are assembled into BN fiber papers with enhanced fiber alignment. These papers are then cut and integrated into a silicone matrix to form well-oriented thermal conductive channels. This approach enables a significantly higher filler mass fraction of 70%, resulting in a thermal pad with a high κ of 19.23 W/(m·K), low thermal resistance of 1.61 cm2·K/W, and excellent electrical insulation and flexibility. Application tests further demonstrate superior heat dissipation performance and operational stability compared to commercial silicone pads. This work not only highlights the potential of BN fiber-based TIMs but also offers a feasible process for their large-scale manufacturing.