Multifunctional Filler‐Engineered PCM Composites With Superior Thermal Conductivity and Leakage Resistance for Advanced Thermal Management

ABSTRACT Conventional phase‐change materials (PCMs) exhibit low thermal conductivity and poor shape stability, limiting their use in electronic thermal management. In this study, a multifunctional PCM composite was developed by chemically grafting xylitol into an epoxy to enhance structural stability and thermal reliability. Hybrid fillers, dopamine‐coated aluminum nitride (P‐AN) and cellulose nanofiber‐derived porous silicon carbide (C‐SC), were incorporated to form a synergistic dual‐network architecture that combines interfacial compatibility with continuous heat‐conduction pathways. The optimized composite (P‐AN:C‐SC = 1:2; 70 wt%) achieved a thermal conductivity of 7.657 W/mK, latent heat of 51 J/g, and complete leakage resistance (100% retention at 140°C) while maintaining electrical insulation (10 9 Ωcm) and mechanical strength. When applied as a thermal interface material (TIM) in a central processing unit system, it reduced the peak temperature by 14.4% compared with the no‐TIM case. This study demonstrates that integrating xylitol‐epoxy grafting chemistry with a P‐AN/C‐SC dual‐network design provides a practical strategy to overcome the intrinsic trade‐off between energy‐storage capacity and thermal conductivity in PCM‐based composites.