Positive electrode active material for non-aqueous electrolyte secondary battery, and method for producing same

A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, comprising:

• providing a composition containing a first lithium transition metal composite oxide having a 50% particle size 1D50 in a first volume cumulative particle size distribution of 0.1 μm or more and less than 3.2 μm and a first liquid medium;
• and
• granulating the composition to obtain a second lithium transition metal composite oxide having a 50% particle size 2D50 in a second volume cumulative particle size distribution greater than 1D50, wherein
• the second lithium transition metal composite oxide has different volume cumulative particle size distributions before and after an ultrasonic treatment in a second liquid medium, and wherein
• the second lithium transition metal composite oxide has a ratio of a 90% particle size 3D90 in a third volume cumulative particle size distribution measured after the ultrasonic treatment to a 90% particle size 2D90 in the second volume cumulative particle size distribution measured before the ultrasonic treatment (3D90/2D90) of 0.53 or less.