Physical Chemistry of Molten-Salt Batteries. Final Report, 1 October 1980-September 1981. Current-Induced Composition Gradients in Molten LiCl-KCl

摘要

Current-induced composition gradients have been predicted in mixed molten salt battery electrolytes. Composition shifts, if large enough, can produce significant deleterious effects, such as solid phase precipitation in or near the electrodes of molten salt batteries, including the LiAl/LiCl-KCl/FeS/sub x/ battery. Quantitative measurements are needed to determine the extent of the gradients and to find means to reduce them. This report presents the first quantitative SEM/EDX measurements with high distance resolution (<50 mu m) of the shape of the composition profile in LiCl-KCl electrolyzed between LiAl electrodes. Also, current-induced precipitation of LiCl in a porous LiAl anode is indicated by SEM/EDX examination. The measured compositions are consistent with predictions from mass transport models based on the electrode reactions, migrational and diffusional mobilities. 5 figures, 4 tables. (ERA citation 08:002363)