METHOD OF PRODUCING A COMPOSITE MATERIAL USED FOR A POSITIVE ELECTRODE OF A LITHIUM ION SECONDARY BATTERY

A method of producing a composite material for a lithium ion secondary battery disclosed here includes a step of preparing a mixture which contains a positive electrode active material and an inorganic phosphorus compound constituting a composite material and in which the solid content is 90 mass % or higher (a mixture preparing step S); and a step in which the mixture is stirred at a predetermined stirring rate or higher, and a coating made of lithium phosphate from at least a part of a lithium compound present on the surface of the positive electrode active material and the inorganic phosphorus compound is formed on the surface of the positive electrode active material (a coating forming step S). Here, the composite material includes the positive electrode active material and the coating formed on the surface of the positive electrode active material.