METHOD FOR PRODUCING COMPLEX OXIDE, POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

摘要

Disclosed is a method for producing a complex oxide, wherein a complex oxide mainly composed of a lithium manganese oxide, which contains at least Li and tetravalent Mn and has a crystal structure belonging to a layered rock salt structure, is produced by: a starting material mixture preparation step in which a starting material mixture is prepared by mixing at least a metal compound starting material that contains one or more metal compounds selected from among oxides, hydroxides and metal salts each containing one or more metal elements essentially including Mn, and a molten salt starting material that contains lithium hydroxide and lithium nitrate at a molar ratio of the lithium hydroxide to the lithium nitrate (namely lithium hydroxide/lithium nitrate) of 1-10 (inclusive); a melting reaction step in which the starting material mixture is melted and caused to react at a temperature not less than the melting point of the molten salt starting material; and a collection step in which the complex oxide generated from the starting material mixture after the reaction is collected.