Phase Change–Liquid Metal Elastomer Composites as Multifunctional Thermal Interface Materials

Thermal interface materials (TIMs) are essential for maintaining performance and reliability in high-power electronics, yet conventional designs struggle to balance thermal conductivity, mechanical compliance, and long-term stability. Phase change materials (PCMs) offer a promising route to buffer sudden temperature spikes through latent heat storage, but their intrinsically low conductivity limits practical use. To address this challenge, we developed phase change–liquid metal (LM) elastomer composites that couple high thermal transport with passive energy storage. By embedding PEG-based PCM microspheres within LM inclusions or the surrounding elastomer, we created tunable architectures that achieve up to a five-fold increase in conductivity (0.92 W·m⁻¹·K⁻¹) while maintaining stable mechanical properties across temperature cycles. Device-level demonstrations showed reduced substrate heating and effective thermal buffering during transient power events. These results highlight a versatile strategy for designing soft, adaptive TIMs that can meet the evolving thermal demands of electronic systems.