First-principles molecular dynamics modeling of the LiCl–KCl molten salt system

• Published in: Computational materials science Vol. 83; pp. 362 - 370
• Main Authors: Bengtson, Amelia, Nam, Hyo On, Saha, Saumitra, Sakidja, Ridwan, Morgan, Dane
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2014; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; First-principles; LiCl–KCl; Modeling; Molecular dynamics; Molten salt; Physics; Thermal properties of condensed matter; Thermal properties of liquids: heat capacity, thermal expansion; Molecular dynamics; LiCl–KCl; Modeling; First-principles; Molten salt; Heat of mixing; Lithium chloride; Molecular dynamics method; Molten salts; Volume expansion; Potassium chloride; Diffusivity; LiCl-KCl; Thermal expansion; Interatomic potential; Modelling; Bulk modulus; Autodiffusion coefficient
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2013.10.043

•First-principles modeling of the molten LiCl–KCl were performed.•We established optimal approaches for the FPMD modeling of the molten LiCl–KCl.•FPMD is a useful predictive tool for properties of the molten LiCl–KCl.•Same techniques can be applied to entirely different molten salts. Properties of molten salts are of interest for a wide-range of applications, including nuclear waste partitioning, heat transfer fluids, and synthesis methods. While there has been extensive work showing the value of molecular modeling with interatomic potentials to predict molten salt properties there have been very limited studies of molten salts from a fully first-principles approach. In order to establish optimal approaches and their strengths and limitations in first-principles molten salt modeling, this work provides extensive first-principles molecular dynamics simulations of the LiCl–KCl molten salt system that are validated against existing literature. The basic thermokinetic properties of volume, thermal expansion, bulk modulus, and diffusivity, are calculated for LiCl, KCl and the eutectic LiCl–KCl liquids at multiple temperatures. Convergence testing reveals 216-atom unit cells and simulation times of 6–12ps are sufficient to provide results with acceptable uncertainties and agreement with experimental data. The results provide a framework of first principles molecular dynamics simulations in the LiCl–KCl molten salt system that can be extended in future research to predict less well-established properties, e.g., the behavior of solutes.