Lithium isotope enrichment by electrochemical pumping using solid lithium electrolytes

Abstract

Concentrating 6 Li isotopes, which exist only approximately 7.6% in nature, to 40 to 90%, is necessary for development of thermal fusion reactors, which are promising as next-generation base-load energy systems. We investigated the possibility of 6 Li enrichment by electrochemical pumping using La 0.57 Li 0.29 TiO 3 solid lithium electrolytes. We also clarified the influence of potential application profiles on separation efficiency. Giving a potential difference to electrodes prepared on both sides of the electrolyte made the electrode on the lithium solution side positive and concentrated 6 Li. The efficiency of lithium isotope enrichment was affected by the potential application profile. An intermittent potential application concentrates 6 Li with high efficiency. In an intermittent potential application in which the electrode on the lithium solution side was positive, an 6 Li concentration with higher efficiency was achieved when a small negative potential was applied to the lithium solution side electrode while suspending application of the positive potential.

Investigation on Lithium Isotope Fractionation with Diffusion, Electrochemical Migration, and Electrochemical Isotope Effect in PEO-PC Based Gel Electrolyte

“…Figure 5.A comparison of the literature reported processes and their corresponding separation factors with this research 3,5,10,25,26,[37][38][39][40]. …”

A Comprehensive Review of Selected Major Categories of Lithium Isotope Separation Techniques

“…[92] The research of Black et al [93] proved that a slight enrichment of Li isotopes can be achieved with the diffusion-assisted separation, and a single-stage separation coefficient of 1.001 is possible. Furthermore, Honda et al [94] investigated the possibility of 6 Li enrichment by electrochemical pumping using La 0.57 Li 0.29 TiO 3 solid Li electrolyte, as shown in Figure 12c. This research studied the influence of the potential profile on the separation effect and clarified that the highest efficiency of Li isotope enrichment was achieved with an intermittent potential profile.…”

“…This research studied the influence of the potential profile on the separation effect and clarified that the highest efficiency of Li isotope enrichment was achieved with an intermittent potential profile. [94] Although water is an inexpensive Figure 14. 6 Li/ 7 Li isotope ratio distributions at different times with graphite anode (left) and LiCoO 2 -coated aluminum anode (right).…”

“…This research studied the influence of the potential profile on the separation effect and clarified that the highest efficiency of Li isotope enrichment was achieved with an intermittent potential profile. [ 94 ] Although water is an inexpensive solvent, this very low separation coefficient is obviously not effective or practical. The Li isotope diffusion coefficient ratio D 7L i/ D 6Li has been reported to be as small as 0.9674 in molten silicate, [ 92 ] which implies that the diffusion coefficients of 6 Li and 7 Li vary by 3.4%.…”