| 摘要 |
PROBLEM TO BE SOLVED: To effectively remove a free acid from an electrolyte without changing the design of a battery and adding a new component to the battery by including a process bringing the electrolyte into contact with anion exchange resin and specifying the concentration of a free acid obtained in this production process to the specified value or less conversion in terms of hydrofluoric acid. SOLUTION: The concentration of free acid obtained in a process bringing an electrolyte into contact with anion exchange resin is made 10 ppm or less converted in terms of hydrofluoric acid. The electrolyte is prepared by dissolving a lithium electrolyte in the specified nonaqueous solvent or its mixture in an inert gas atmosphere so that the concentration of the lithium electrolyte becomes about 0.5-2.0 mole/l, preferably 0.8-1.2 mole/l. As an organic polymer resin compound series ion exchange resin, preferably, a gelled type or macroporous type ion exchange resin of styrene divinyl benzene copolymer is used. The removing efficiency of the free acid is enhanced, and the solvent can continuously be treated by using a column process. |
