Positive electrode active material for lithium ion secondary battery, method of manufacturing positive electrode active material for lithium ion secondary battery, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-2022131141-A1
Application number	US-202017310782-A
Country	US
Kind code	A1
Filing date	Feb 26, 2020
Priority date	Feb 26, 2019
Publication date	Apr 28, 2022
Grant date	—

Abstract

A positive electrode active material for a lithium ion secondary battery contains a lithium metal composite oxide. The lithium metal composite oxide includes lithium (Li), nickel (Ni), cobalt (Co), and element M (M) in a mass ratio of Li:Ni:Co:M=1+a:1−x−y:x:y (wherein −0.05≤a≤0.50, 0≤x≤0.35, 0≤y≤0.35, and the element M is at least one element selected from Mg, Ca, Al, Si, Fe, Cr, Mn, V, Mo, W, Nb, Ti, Zr, and Ta), wherein when a line analysis is performed with STEM-EELS from a surface of a particle of the lithium metal composite oxide to a center of the particle in a cross-section of the particle during charging at 4.3 V (vs. Li + /Li), a thickness of an oxygen release layer, in which an intensity ratio of a peak near 530 eV (1st) to a peak near 545 eV (2nd) at an O-K edge is 0.9 or less, is 200 nm or less.

First claim

1 . A positive electrode active material for a lithium ion secondary battery containing a lithium metal composite oxide, the lithium metal composite oxide comprising:
lithium (Li), nickel (Ni), cobalt (Co), and element M (M) in a mass ratio of Li:Ni:Co:M=1+a:1−x−y:x:y (wherein −0.05≤a≤0.50, 0≤x≤0.35, 0≤y≤0.35, and the element M is at least one element selected from Mg, Ca, Al, Si, Fe, Cr, Mn, V, Mo, W, Nb, Ti, Zr, and Ta), wherein when a line analysis is performed with Scanning Transmission Electron Microscope-Electron Energy-Loss Spectroscopy from a surface of a particle of the lithium metal composite oxide to a center of the particle in a cross-section of the particle during charging at 4.3 V (vs. Li + /Li), a thickness of an oxygen release layer, in which an intensity ratio (1st/2nd) of a peak near 530 eV (1st) to a peak near 545 eV (2nd) at an O-K edge is 0.9 or less, is 200 nm or less, and wherein a specific surface area of the positive electrode active material for a lithium ion secondary battery is 0.7 m 2 /g or more and 2.0 m 2 /g or less.

2 . The positive electrode active material for a lithium ion secondary battery according to claim 1 , wherein a mean volume particle diameter (MV) is 5 μm or more and 20 μm or less in a particle size distribution by a laser diffraction scattering method.

3 . The positive electrode active material for a lithium ion secondary battery according to claim 1 , wherein the element M is either uniformly distributed inside secondary particles of the lithium metal composite oxide or uniformly coated on surfaces of the secondary particles, or both.

4 . A method of manufacturing a positive electrode active material for a lithium ion secondary battery, comprising:
a heat treatment step of heat-treating a metal composite hydroxide at a temperature of 105° C. or higher and 700° C. or lower to obtain a heat-treated metal composite compound; a mixing step of mixing the heat-treated metal composite compound with a lithium compound to form a lithium mixture; a firing step of firing the lithium mixture formed in the mixing step at a temperature of 650° C. or higher and 900° C. or lower in an oxidizing atmosphere; wherein the metal composite hydroxide contains nickel (Ni), cobalt (Co), and an element M in a mass ratio of Ni:Co:M=1−x−y:x:y (wherein 0≤x≤0.35, 0≤y≤0.35, and the element M is at least one element selected from Mg, Ca, Al, Si, Fe, Cr, Mn, V, Mo, W, Nb, Ti, Zr, and Ta), and wherein a specific surface area of the positive electrode active material for a lithium ion secondary battery obtained after the firing step is 0.7 m 2 /g or more and 2.0 m 2 /g or less.

5 . A lithium ion secondary battery having a positive electrode containing the positive electrode active material for the lithium ion secondary battery of claim 1 .

6 . A lithium ion secondary battery having a positive electrode containing the positive electrode active material for the lithium ion secondary battery of claim 2 .

7 . A lithium ion secondary battery having a positive electrode containing the positive electrode active material for the lithium ion secondary battery of claim 3 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Toma Takahiro
• Ogawa Takahiro
• Matsuura Yoshiyuki
• Ryoshi Kazuomi

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01P2006/12

  Surface area · CPC title