Design of elevated temperature phase change materials of carbonate-villiaumite eutectic mixtures: Method, validation, and application

Abstract

In concentrated solar power (CSP) technology, molten salt is one of the highly competitive phase change energy storage materials due to large energy storage densities and good chemical resistance. However, the lack of precise methodological guidance for designing high enthalpy eutectic salts limits the widespread and efficient application of molten salts. Here, we first present a method for accurately assessing the enthalpy of eutectic salt by first-principles molecular dynamics (FPMD) simulations. By simulating two extreme states infinitely close to the pure solid and pure liquid at the phase transition temperature, the fusion enthalpy of a new ternary eutectic salt (K2CO3-Li2CO3-NaF) is accurately predicted with a calculation error as low as 6.4%. This work provides theoretical guidance for predicting the enthalpy of molten salts and lays the foundation for their widespread application.