Nonaqueous electrolyte secondary battery positive electrode active material and method for producing same, and nonaqueous electrolyte secondary battery which uses positive electrode active material

Abstract

Provided are: a composite oxide which is to be used as a positive electrode active material and is capable of achieving high low-temperature output properties even when no water washing treatment is performed; a method for producing the same; and a positive electrode active material which suppresses the formation of soluble lithium and does not cause gelling problems when adjusting the paste. Theprovided nonaqueous electrolyte secondary battery positive electrode active material is a lithium metal composite oxide powder comprising secondary particles obtained by agglomerating primary particles including lithium, nickel, manganese and cobalt, or comprising both the primary particles and the secondary particles, the active material being characterized in that: the interior of the secondaryparticles is a primarily porous structure; the pH of the slurry is 11.5 or less; the soluble lithium content is 0.5 (mass%) or less; the specific surface area is 3.0-4.0 (m<2> / g); and the porosity ismore than 50 and no more than 80 (%).

Description

technical field [0001] The present invention relates to a positive electrode active material for a nonaqueous electrolyte secondary battery, a method for producing the same, and a nonaqueous electrolyte secondary battery using the positive electrode active material. Background technique [0002] In recent years, with the popularization of portable electronic devices such as smartphones, tablet terminals, and notebook computers, small and lightweight non-aqueous electrolyte secondary batteries with high energy density have been used as batteries for hybrid vehicles and electric vehicles. Batteries, high output secondary battery development needs are expanding. [0003] A lithium ion secondary battery is mentioned as a secondary battery which can satisfy these demands. A lithium ion secondary battery is composed of a positive electrode, a negative electrode, and an electrolytic solution, and the active material of the positive electrode and the negative electrode uses a mater...

AI Technical Summary

Problems solved by technology

However, due to the water washing treatment, there are disadvantages that the surface of the lithium metal composite oxide is damaged, and even the necessary lithium is eluted, and the output characteristics are deteriorated

[0010] However, when the heat treatment temperature is low, the reactivity between the lithium supply source and the metal hydroxide also decreases, so that unreacted excess lithium increases, and the crystallinity of the positive electrode active material deteriorates, etc., and it is necessary to easily elute from the positive electrode active material itself. Lithium

Therefore, when preparing the paste of the positive electrode active material, there is a concern that lithium will be dissolved in the solvent to cause gelation, resulting in a decrease in yield.

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