The electric double layer structure and interface energy of uranium electrode in molten LiCl-KCl-UCl3 mixture: A molecular dynamics simulation study

The electric double layer structure and interface energy of uranium electrode in molten LiCl-KCl-UCl3 mixture, as well as the surface energies of metallic uranium and molten salts, were investigated using molecular dynamics simulations. The surface energies were calculated, respectively, from the pressure tensor and the energy difference for molten salt and uranium, and interface energy was evaluated from the Gibbs free energy difference between systems with and without interface. The surface energies of molten alkali halides are between 76.4 and 201.8 mJ & sdot;m(- 2) and decrease with the increase of radius of the halide anion or the alkali cation for molten salt with the same alkali cation or the same halide anion. The surface energy of uranium depends on the allotrope morphology and crystal facet, and the surface energies of alpha -U, beta - U, and gamma -U are 2.36, 1.45, and 1.69 J & sdot;m(- 2) in average for the seven low index crystal facets. The interface energy of uranium and molten LiCl-KCl-UCl3 mixture is about 2.71 J & sdot;m(- 2) and increases with the increase of charge density on the uranium slabs. The molten LiCl-KClUCl(3 )mixture in anodic zone has higher coordination number than that in cathodic zone but similar coordination distance.