| 摘要 |
PROBLEM TO BE SOLVED: To provide an electricity storage device excellent in charge/discharge cycle characteristics.SOLUTION: An electricity storage device (lithium ion secondary battery 200) of the present invention comprises: a positive electrode 30; a negative electrode 20; a separator 13; and an electrolyte. The negative electrode 20 includes a negative electrode active material containing silicon or tin. The separator 13 is disposed between the positive electrode 30 and the negative electrode 20. The electrolyte has lithium ion conductivity and contains at least one selected from a compound A and a compound B. The compound A is a fluorine-containing cyclic saturated hydrocarbon including a substituent Rintroduced in a cyclopentane ring. The compound B is a fluorine-containing cyclic saturated hydrocarbon including a substituent Rand a substituent Rwhich are introduced in a cyclopentane ring. |
