High power and energy density dynamic phase change materials using pressure-enhanced close contact melting

Phase change materials show promise to address challenges in thermal energy storage and thermal management. Yet, their energy density and power density decrease as the transient melt front moves away from the heat source. Here, we propose an approach that achieves the spatial control of the melt-front location of pure phase change materials using pressure-enhanced close contact melting. Using paraffin wax, we demonstrate effective energy density and power density of 230 J cm−3 and 0.8 W cm−3, respectively. Using gallium, we achieve effective energy density of 480 J cm−3 and power density of 1.6 W cm−3. Through experimentally validated physics-based analytical and finite element models, we show that our system enables the stabilization of surface temperatures at heat fluxes approaching 3 kW cm−2. This approach uses pure and cost-effective materials, overcoming complexities and cost of composite phase change materials. We report design guidelines for integrating our approach in thermal management and thermal energy storage applications.