Phase change material-based thermal energy storage

Phase change materials (PCMs) having a large latent heat during solid-liquid phase transition are promising for thermal energy storage applications. However, the relatively low thermal conductivity of the majority of promising PCMs (<10 W/(m ⋅ K)) limits the power density and overall storage efficiency. Developing pure or composite PCMs with high heat capacity and cooling power, engineering effective thermal storage devices, and optimizing system integration have long been desired. Our perspective outlines the needs for better understanding of multi-physics phase change phenomena, engineering PCMs for better overall transport and thermodynamic properties, co-optimizing device design, and integrating PCMs with potential applications. We start by covering the heat transfer fundamentals of PCMs. We then discuss PCM property characterization and need for materials design. We conclude by discussing higher-level device design and integration principles, as well as emerging applications and requirements. We also identify future research opportunities for PCM in thermal energy storage.