Electrode active material, manufacturing method of the same, electrode for lithium ion secondary battery, and lithium ion secondary battery

PROBLEM TO BE SOLVED: To provide an electrode active material with high battery performance, a manufacturing method of the same, an electrode for a lithium ion secondary battery, and a lithium ion secondary battery.SOLUTION: The manufacturing method of the electrode active material includes: a cleaning step of cleaning a lithium composite oxide with a solvent of a dielectric constant of greater than or equal to 5; and a heating step of heating the lithium composite oxide after the cleaning step at a temperature of greater than 250°C and less than 600°C.SELECTED DRAWING: Figure 3