Cathode active material for lithium batteries

PROBLEM TO BE SOLVED: To study the relationship between iron contained in a positive electrode active material powder and battery life characteristics, and to propose a positive electrode active material for lithium batteries excellent in battery life characteristics. SOLUTION: 5 g of a positive electrode active material powder is added to 15 g of a 2N hydrochloric acid aqueous solution and stirred for 10 minutes at a liquid temperature of 25 ° C., and the positive electrode active material is filtered off. A positive electrode active material for a lithium battery is proposed in which the amount is equivalent to 5 ppm or less of the total amount of the positive electrode active material powder. It has been found that the iron eluted when the positive electrode active material powder is immersed in a predetermined acid closely affects the life characteristics of the battery. [Selection figure] None