First-principles molecular dynamics investigation on KF-NaF-AlF3 molten salt system

Abstract

Abstract In this paper, first-principles molecular dynamics simulations are applied to study the ionic structure and electronic properties of KF-NaF-AlF3 system. The results show that the main forms of complex ion groups are [AlF4]−, [AlF5]2− and [AlF6]3−. With KF concentration increasing, the covalent interaction between Al F ions first increases and then decreases, resulting in the increase of Al F coordination number and then decreases. The calculation results of Raman spectra on [AlF4]−, [AlF5]2− and [AlF6]3− are close to the experimental values, which indicates FPMD is applicable to similar molten salt systems.