The electrolyte solution in these batteries consists of a lithium hexafluorophosphate and more salt in an organic solvent. Commonly used salts are lithium hexafluorophosphate (LiPF₆), lithium perchlorate (LiClO₄), lithium tetrafluoroborate (LiBF₄), lithium hexafluoroarsenate (LiAsF₆), lithium hexafluorosilicate (LiSiF₆) and lithium tetraphenylborate (LiB(C₆H₅)₄).
These lithium salts may be combined with organic solvents to form the electrolyte in lithium batteries. With an ideal range of 0.8-1.2 mol/L, the electrolyte content in the solvent ranges from 0.1 to 2 mol/L. To confirm that the solutions have been made at the correct concentrations, IC can be used to determine the anions of the added lithium salts.
Authors of a recent Thermo Fisher Scientific study prepared simulated samples containing either lithium hexafluorophosphate, lithium perchlorate, or lithium hexafluorophosphate in an equal mixture of ethylene carbonate, diethyl carbonate, and propylene carbonate, and showed that the anionic content can be accurately determined using a Reagent-FreeTM IC (RFICTM) system. The analyst can avoid the issues with eluent preparation by using the RFIC technology.