Positive electrode active material, non-aqueous electrolyte secondary battery containing the same and method for evaluating positive electrode active material

摘要

A positive electrode active material powder for a non-aqueous electrolyte secondary battery, wherein an amount of a liquid reagent absorbed by the powder is 20 to 40 ml per 100 g of the powder when the liquid reagent is dibutyl phthalate, and the amount is 20 to 50 ml per 100 g of the powder when the liquid reagent is N-methyl-2-pyrrolidone or water, the absorption amount is a value measured using a device according to test method A or B regarding DBP absorption based on JIS K6217 (1997), and the measured value is an amount of the liquid reagent added until the viscosity of a mixture of the powder and the liquid reagent reaches a level corresponding to 70% of a maximum torque which is recorded when a change in the viscosity of a mixture of the powder and the liquid reagent is measured by a torque detecting device.