Abstract: Provided is a positive electrode active material for a non-aqueous electrolyte secondary battery. Also provided is a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, comprising: providing a lithium transition metal composite oxide having a ratio D50/DSEM of 1 or more and 4 or less, having a layered structure, and having a ratio of a number of moles of nickel to a total number of moles of metals other than lithium of 0.3 or more and less than 1, and a ratio of a number of moles of cobalt to the total number of moles of metals other than lithium of 0 or more and less than 0.5; bringing the lithium transition metal composite oxide into contact with a cobalt compound to obtain an adhered material; and heat-treating the adhered material at a temperature higher than 700° C. and lower than 1100° C.

Abstract: A method of producing a positive electrode for a non-aqueous electrolyte secondary battery, includes: providing a lithium transition metal composite oxide having a layered structure, having a ratio D50/DSEM of 1 or more and 4 or less, and having a certain content of nickel and a certain content of cobalt; bringing the lithium transition metal composite oxide into contact with a cobalt compound to obtain an adhered material; heat-treating the adhered material at a temperature higher than 700° C. and lower than 1100° C. to obtain a heat-treated product; obtaining a positive electrode composition containing the heat-treated product, a conductive auxiliary agent, and a binder; and applying and pressurizing the positive electrode composition onto a collector to form an active material layer having a density of 2.7 g/cm3 or more and 3.9 g/cm3 or less on the collector.