Lithium hexafluoroarsenate and hexafuoroarsenic acid

Abstract

Lithium hexafluoroarsenate recently became of interest as an electrolyte in high-energy density batteries but was commercially unavailable. LiAsF6 was first synthesized by Cox2 and later by Kemmitt, Russell, and Sharp3 using the reaction4 of the metal fluoride and As203 with liquid BrF3. Atkinson and Halladas apparently prepared LiAsFe of good purity from KAsF6 by a batch cation-exchange technique. Solutions of LiAsF6 and solid LiAsF6 have been prepared, respectively, by metathetical reactions in methyl formate6#? and liquid ammonia.6 Structural2! a and electrochemical5-* data for LiAsF6 have been reported. We have investigated four potential methods for the preparation of highpurity LiAsF6: (1) neutralization of the known9 HAsF6 with LiOH, (2) ion exchange5 with KAsF6; (3) reaction of LiF and AsF5,' O and (4) fluorination of LiHzAsOd with H F via the AsFhOH-i0n.~~11 We report here an improved method for the synthesis of LiAsF6, some of its properties, and some observations on commerical hexafluoroarsenic acid.

Safer Electrolytes for Lithium‐Ion Batteries: State of the Art and Perspectives

“…According to reports in the literature, the onset temperature for the decomposition of dry, + [20] o [59] + [61] + [62] + [63] electrochemicalstability + [23,64,98] o [60] o [52] + [23,65] + [23] + [33] thermal stability À [43,[66][67][68][69] o [70] o [71] + [72] À [62] + [42,43] stability towardsm oisture À [38,39,[73][74][75] o [60] o [71] o [65] o [76] + [77] Al current collectorp assivation + [36,44,47] ++ [71,78] + [79] o [62] À [46][47][48][49]80] nontoxicity solid LiPF 6 is about 100 8C. [43,[66]…”

“…LiAsF 6 provides very good ionic conductivitya nd superior cycling performance. [61] Strong AsÀFb onding results in highert hermal stability, [72] increased resistivity towards hydrolysis, and enhanced electrochemical stability towards oxidation (up to potentials of about 4.7 V). [23,65] However,the (potential) formation of highly toxic AsF 3 [82] excludes its utilization in commercial LIBs.…”

Efficiencies of Cycling Lithium on a Lithium Substrate in Propylene Carbonate

“…It was indicated by the manufacturer to contain from 50 to 100 ppm H20 (Karl Fischer method). Details concerning the preparation and analysis of high purity anhydrous LiAsF6 have been discussed by Lawless et al (21).…”