A review of metallic materials for latent heat thermal energy storage: thermophysical properties, applications, and challenges

Phase change materials provide desirable characteristics for latent heat thermal energy storage by keeping the high energy density and quasi isothermal working temperature. Along with this, the most promising phase change materials, including organics and inorganic salt hydrate, have low thermal conductivity as one of the main drawbacks. Metallic materials are attractive alternatives due to their higher thermal conductivity and high volumetric heat storage capacity. This paper presents an extensive review of the thermophysical properties of metals and alloys as the potential phase change materials for low (<40 °C), medium (40 °C–300 °C), and high (>300 °C) temperatures. The information presented includes the fundamental thermophysical properties as melting temperature, the heat of fusion, density, specific heat, and thermal conductivity found in the published literature. The temperature dependence of critical properties as specific heat, density, thermal conductivity, expansion coefficient, viscosity is also reviewed, including mathematical theoretical predictions crucial from an engineering design point of view. Besides, the current work briefly summarizes the potential applications and main challenges of metals and alloys as phase change materials. It is intended that this review provides a database of metallic phase change materials thermophysical properties to facilitate the selection, evaluation, and potential impact in different fields as solar energy storage, heating and cooling, electronic, bioengineering, and beyond.