Positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

Abstract

This positive electrode active material, which is contained in a nonaqueous electrolyte secondary battery, contains a lithium transition metal composite oxide; and the lithium transition metal composite oxide contains Ni, Ca and Sr, and comprises secondary particles, each of which is composed of aggregated primary particles. With respect to the distribution of element concentrations in a cross-section of the lithium transition metal composite oxide as determined using time-of-flight secondary ion mass spectrometry, the ratio ICa_OUT/ICa_IN of the normalized intensity ICa_OUT of Ca in the surfaces of the secondary particles to the normalized intensity ICa_IN of Ca in the insides of the secondary particles satisfies 2≤ICa_OUT/ICa_IN≤7, while the ratio ISr_OUT/ISr_IN of the normalized intensity ISr_OUT of Sr in the surfaces of the secondary particles to the normalized intensity ISr_IN of Sr in the insides of the secondary particles satisfies 2≤ISr_OUT/ISr_IN≤7.

Dependencies are inferred from the claim text.