| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite oxide useful as a positive electrode active material for a lithium secondary battery excellent in high rate property; a method for producing the same; a positive electrode for a lithium secondary battery obtained using the composite oxide; and a lithium secondary battery provided with the positive electrode for a lithium secondary battery.SOLUTION: The composite oxide has a composition represented by formula (I) and has a BET specific surface area of 0.1-3.0 m/g, tap density of 0.8-2.5 g/cm, press density at 78 MPa of 1.5-3.2 g/cm, and a particle diameter D50 of secondary particles of 1-30 μm. In the formula, M represents an element selected from the group consisting of Al, Ti, Fe, Co and Zr; x represents a number of 0.35-0.55, y represents a number of 1.20-1.52, and z represents a number of 0.0098-0.30, provided that the sum of x, y and z is 2; a represents a number of 0.97-1.20, and b represents a number of 3.97-4.04. |
