| 摘要 |
Disclosed is a lithium ion secondary battery having a positive electrode, a negative electrode and a non-aqueous electrolyte composition (electrolytic solution), characterized in that: the positive electrode includes a positive electrode active material represented by: a Li[Li 1/3 M1 2/3 ]O 2· (1- a )LiM2O 2 (where M1 represents at least one kind of metal element selected from the group consisting of Mn, Ti, Zr and V; M2 represents at least one kind of metal element selected from the group consisting of Ni, Co, Mn, Al, Cr, Fe, V, Mg and Zn; and a represents a composition ratio and satisfies a relationship of 0 < a < 1); the negative electrode includes a negative electrode active material containing silicon; and the non-aqueous electrolyte composition includes a lithium salt (C n F 2 n +1 SO 2 )(C m F 2 m +1 SO 2 )NLi (where m and n each independently represent an integer of 2 or more as a support electrolyte. This lithium ion secondary battery attains a high capacity and good cycle characteristics. |
