Positive electrode active material, electrode compound and battery

Abstract

This invention relates to a positive electrode active material containing a composite oxide comprising lithium (Li), nickel (Ni), and manganese (Mn). When the mass of the positive electrode active material measured at 400°C in a thermogravimetric analysis of the positive electrode active material under air atmosphere is defined as W1, the maximum mass of the positive electrode active material measured in the same thermogravimetric analysis at a temperature between 500°C and 600°C is defined as W2, and the surface area of ​​the positive electrode active material used in the thermogravimetric analysis is defined as SA, the ratio of the mass increase W2 - W1 to the surface area SA (W2 - W1) / SA is 0.25 g / cm² or less.

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