被覆活物質、被覆活物質の製造方法、正極材料、および電池

Abstract

A coated active material 100 according to the present disclosure comprises a positive electrode active material 11 and a coating layer 12 that covers at least a part of the surface of the positive electrode active material 11. The coating layer 12 contains a lithium-containing fluoride. If the mass M2 of lithium, which is derived from a lithium-containing alkaline component and is present on the surface of the positive electrode active material 11, is measured by means of neutralization titration, the ratio of the mass M2 of lithium to the mass M1 of the positive electrode active material 11 is more than 0.26% but not more than 0.55%. A method for producing a coated active material 100 according to the present disclosure comprises: a step for cleaning a positive electrode active material 11 with a cleaning solution that contains a water-soluble organic solvent so that the ratio of the mass M2 of lithium to the mass M1 of the positive electrode active material 11 is more than 0.26% but not more than 0.55% if the mass M2 of lithium is measured by means of neutralization titration; a step for drying the positive electrode active material 11 after the cleaning; and a step for coating at least a part of the surface of the positive electrode active material 11 after the drying with use of a coating material that contains a lithium-containing fluoride.

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