| abstract |
It is an object of this exemplary embodiment to provide a lithium ion secondary battery using a positive electrode active material having an operating potential of 4.5 V or more, the lithium ion secondary battery having excellent high temperature cycle characteristics. This exemplary embodiment is a lithium ion secondary battery comprising a positive electrode and a negative electrode capable of intercalating and deintercalating lithium, a separator between the positive electrode and the negative electrode, and an electrolytic solution containing a nonaqueous electrolytic solvent, wherein the positive electrode comprises a positive electrode active material operating at a potential of 4.5 V or more versus lithium, the separator comprises cellulose, a cellulose derivative, or a glass fiber, and the nonaqueous electrolytic solvent comprises a fluorinated solvent. |