Positive electrode active material and its manufacturing method

Abstract

The objective of this invention is to provide a positive electrode active material for improving the quantitative properties of a feeder. The positive electrode active material contains a composite oxide comprising lithium (Li), nickel (Ni), and manganese (Mn). The positive electrode active material has an angle of repose of 55.0 degrees to 65.0 degrees and an angle of collapse of 43.0 degrees to 60.0 degrees. Preferably, the angle of collapse is less than 13.0 degrees. It is also preferable that the arithmetic mean perimeter of the primary particles is 8.0 μm or less. The positive electrode active material preferably has a spinel-type crystal structure and an a-axis length of 8.150 Å to 8.200 Å.