Positive electrode active material and its manufacturing method

Abstract

This invention relates to a method for manufacturing a positive electrode active material. The method involves mixing a composite hydroxide containing nickel (Ni) and manganese (Mn) elements, a lithium compound, and a sintering aid to obtain a mixture, followed by calcination of the mixture in an oxygen-containing atmosphere. The oil absorption of the composite hydroxide, as measured according to JIS K 5101:2004, is 3.0 mL / 5 g or more and 6.5 mL / 5 g or less. The oxygen-containing atmosphere contains less than 21.0% by volume of oxygen. Preferably, a boron compound is used as the sintering aid.