Phase change materials for thermal energy storage: A perspective on linking phonon physics to performance

Abstract

Thermal energy storage is being actively investigated for grid, industrial, and building applications for realizing an all-renewable energy world. Phase change materials (PCMs), which are commonly used in thermal energy storage applications, are difficult to design because they require excellent energy density and thermal transport, both of which are difficult to predict from simple physics-based models. In this Perspective, we describe recent advances in the understanding of the equilibrium and transport properties of PCM materials that can help accelerate technology development. We then emphasize how the microscopic phonon picture of both liquids and solids enables a better understanding of novel PCM systems and their predictive power. We then show how this microscopic picture can be used to understand kinetic processes, such as supercooling, and how it can impact the thermal power output in thermal energy storage systems.