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AssigneeJX Nippon Mining & Metals Corporation
InventorsRyuichi Nagase, Yasuhiro Kawahashi
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The present invention provides a positive electrode active material for lithium ion batteries, which realizes a lithium ion battery that is, while satisfying fundamental characteristics of a battery (capacity, efficiency, load characteristics), low in the resistance and excellent in the lifetime characteristics. In the positive electrode active material for lithium ion batteries, the variation in the composition of transition metal that is a main component inside of particles of or between particles of the positive electrode active material, which is defined as a ratio of the absolute value of the difference between a composition ratio inside of the particles of or in a small area between the particles of the transition metal and a composition ratio in a bulk state to the composition ratio in a bulk state of the transition metal, is 5% or less.
A precursor for positive electrode active material for lithium ion batteries, which is composed of secondary particles made of at least lithium and transition metal and formed by flocculating primary particles, wherein the variation in composition of transition metal that is a main component inside of secondary particles or between the secondary particles of the precursor for positive electrode active material, which is defined as a ratio of the absolute value of the difference between a composition ratio inside of the particles of or in a small area between the particles of the transition metal and a composition ratio in a bulk state to the composition ratio in the bulk state of the transition metal, is 5% or less.
Dependencies are inferred from the claim text.