Electrolyte solution with low acid content

Manufacture of lithium hexafluorophosphate-containing solution involves contacting lithium hexafluorophosphate, acid and organic solvent with base(s) chosen from alkaline-earth hydroxide, alkaline-earth hydrogen carbonate, alkaline-earth carbonate, lithium hydroxide, lithium hydrogen carbonate and lithium carbonate. The organic solvent contains nitrile(s). Independent claims are included for the following: (1) lithium hexafluorophosphate-containing solution, which contains 50 ppm or less, preferably 8.4 ppm or less total acid, 50 ppm or less, preferably 10 ppm or less water and/or 12 ppm or less, preferably 1 ppm or less fluoride; and (2) manufacture of electrolyte.