Commercial scale preparation, properties and the performance of LiAsF/sub 6/, LiPF/sub 6/, LiBF/sub 4/ electrolytes in secondary lithium ion and lithium cells

The performance of lithium and lithium ion accumulators is still dependent upon lithium salts such as LiPF/sub 6/, LiBF/sub 4/, LiAsF/sub 6/, LiSO/sub 3/CF/sub 3/ and LiClO/sub 4/ and/or their mixtures. We have described the manufacturing methods for the first three lithium salts, and their quality and performance in high energy secondary accumulators. These salts can be produced by aqueous, non-aqueous and metathetical routes. Currently, LiPF/sub 6/ is made by nonaqueous route by dissolving LiF in anhydrous HF and reacting it with PF/sub 5/ generated in-situ from PCl/sub 5/ and anhydrous HF. Lithium hexafluoroarsenate is prepared by neutralization HAsF/sub 6/-6H/sub 2/O with LiOH; lithium tetrafluoroborate from neutralization of 50% HBF/sub 4/ and LiOH as well as reaction of BF/sub 3/ with LiH/sub n/F/sub n+1/ solution. A mathematical model has been very useful in deciding the proper parameters for the production of LiBF/sub 4/ from commercially available inexpensive and environmentally less hazardous material, 50% aqueous HBF/sub 4/. Our electrochemical results show that LiPF/sub 6/, LiBF/sub 4/ and LiAsF/sub 6/ salts when used as an electrolyte in small coin cells, 2325 and 2016, are stable up to the discharge voltage of 4.5 volts.