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. The method includes providing a composition containing a first lithium transition metal composite oxide having a 50% particle size Din 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 Din a second volume cumulative particle size distribution greater than D. The second lithium transition metal composite oxide has a ratio of a 90% particle size Din a third volume cumulative particle size distribution measured after the ultrasonic treatment to a 90% particle size Din the second volume cumulative particle size distribution measured before the ultrasonic treatment (D/D) of 0.53 or less.