| abstract |
【Task】 Composite oxide useful as a positive electrode active material of a lithium secondary battery excellent in high-rate characteristics, a method for producing the same, a positive electrode for a lithium secondary battery obtained using the composite oxide, and lithium including the positive electrode for the lithium secondary battery A secondary battery is provided. [Solution] It has a composition represented by formula (I), a BET specific surface area of 0.1 to 3.0 m 2 / g, a tap density of 0.8 to 2.5 g / cm 3 , and a press density at 78 MPa of 1.5 to A composite oxide characterized by 3.2 g / cm 3 and a secondary particle diameter D50 of 1 to 30 μm. [Chemical 1] (In the formula, M represents an element selected from the group consisting of Al, Ti, Fe, Co, and Zr. X is 0.35 to 0.55, y is 1.20 to 1.52, and z is , 0.0098 to 0.30, and the sum of x, y and z is 2. a represents a number from 0.97 to 1.20, and b represents 3.97 to 4.04. Represents the number of [Selection figure] None |