Modeling Isotope Separation in Electrochemical Lithium Deposition

Abstract

Naturally occurring Li consists of two stable isotopes, 6Li with an abundance of about 7.5%, and 7Li making up the remainder with 92.5%. The development of a 6Li enrichment technique, in terms of technical reliability and environmental safety to reach 6Li future requirements, represents a key step in the roadmap for nuclear fusion energy supply worldwide. This paper uses finite element analysis-based models to simulate electrochemical Li isotope separation, which is an attractive method in terms of simplicity, safety, and scalability. In the model, we quantitatively analyze how different electrochemical factors including thermodynamics, charge-transfer kinetics, and diffusivities affect the separation process (separation factor), together with cell parameters, such as cell length and current density. The maximum separation factor of 1.128 could be obtained with the cell under the optimal thermodynamic, kinetic, and diffusive conditions, which is among the highest separation factors ever reported. These results will assist in designing the actual isotope separation setup with large separation factor and appropriate timing for sample collection.

Electromigration separation of lithium isotopes with B12C4, B15C5 and B18C6 systems

“…They also found that the diffusion coefficient difference between 6 Li + and 7 Li + in agar gel is only 0.0036. Wild et al 8 studied the separation of lithium isotopes with an electrodeposition method through finite element simulation. They found that the separation factor is influenced by various factors such as thermodynamics, and the theoretical separation factor can reach 1.128.…”

Effect of the Substrate and the Morphology on Electrochemical Separation of Lithium Isotopes: Insights from DFT

“…The diffusion coefficient can also be sensitive to isotopic effects especially when ions are weakly coupled with the solvent molecules 28 and higher mobility is expected for the lighter isotope. But when the ions are strongly solvated, as is the case in the electrochemical experiments mentioned before, small fractionation during diffusion occurs.…”