| 摘要 |
Provided is a lithium ion secondary battery which is low in capacity drop of the battery during fast-charge and has high energy density. In the present lithium ion secondary battery, the positive electrode contains a lithium nickel manganese oxide represented by formula (I): Li x Ni a M1 b Mn 2-a-b O 4 (I) (In formula (I), M1 represents at least one selected from the group consisting of Ti, Si, Co, Fe, Cr, Al, Mg, B and Li; 0 < x ‰¤ 1; 0.4 ‰¤ a ‰¤ 0.6; and 0 ‰¤ b ‰¤ 0.4) and having a specific surface area of 0.2 to 1 m 2 g -1 ; and the negative electrode contains a lithium titanium oxide represented by formula (II): Li y Ti 5/3-c M2 c O 4 (II) (in formula (II), M2 represents at least one selected from the group consisting of Ta, Zr, Cr, Ni and V; 4/3 ‰¤ y ‰¤ 7/3 and 0 ‰¤ c < 0.1) and having a specific surface area of 4 to 20 m 2 g -1 . |
