| abstract |
Lithium secondary particles having a large primary particle size and uniform, and most of such primary particles are surrounded only by a space, and therefore have excellent cycle characteristics when used as a positive electrode active material. Provided are a positive electrode active material for a lithium secondary battery that provides a secondary battery and a method for producing the same. According to the present invention, the composition formula Li x Ni 1 -yz Co y M z O 2 (M is at least one element selected from Mn, Al, Zr, Si, Sr and Mg, and x , Y and z are numbers satisfying 0.95 ≦ x ≦ 1.10, 0.1 ≦ y ≦ 0.4 and 0 ≦ z ≦ 0.1.) An active material having a median diameter measured by a laser diffraction particle size distribution measuring device in the range of 2 to 20 μm, and an average major axis of primary particle diameter of 1 to 10 μm by SEM observation of a cross section of the particle processed with a cross section polisher. (The median diameter) / (the average major axis of the primary particle diameter of the particle cross section) is in the range of 1.0 to 3.0, and the 5% diameter of the volume-based cumulative distribution is the median diameter / 3 or more and 95% diameter is less than 3 times the median diameter. A positive electrode active material for a secondary battery is provided. Furthermore, according to this invention, the manufacturing method of such a positive electrode active material for lithium secondary batteries is provided. [Selection figure] None |