| abstract |
(57) [Problem] To have a plateau potential in a 4V region almost equivalent to lithium cobalt oxide, and a high energy density, Provided is a non-aqueous electrolyte secondary battery having excellent battery characteristics such as safety, cycle characteristics, and high-temperature storage characteristics. A non-aqueous electrolyte secondary battery of the present invention, the general formula Li X Mn a Co b O 2 ( where, 0.9 ≦ X ≦ 1.1, 0.45 ≦ a ≦ 0.55, 0.45 ≦ b ≦ 0.55, 0.9 <a + b ≦ 1.1), and a positive electrode active material to which a lithium-containing composite oxide having a layered crystal structure represented by the formula: and either one of lithium cobaltate and spinel lithium manganate is added and mixed. Containing positive electrode, a negative electrode containing a negative electrode active material capable of inserting and removing lithium ions, and a separator for separating these positive electrodes and the negative electrode, And a non-aqueous electrolyte. |