| 摘要 |
PROBLEM TO BE SOLVED: To provide a secondary battery superior in safety and cycle characteristics.SOLUTION: A lithium ion secondary battery comprises: a negative electrode including a carbon material which lithium ions can go into and out of; a positive electrode; and an electrolyte. The electrolyte includes: 70 vol.% or more of a phosphorus compound expressed by a predetermined formula; 0.01-30 vol.% of a fluorinated carbonate compound; and metal ions having an oxidation-reduction potential at a potential higher than lithium by 1.0 V or more. |
