Positive electrode active material for lithium secondary battery, and positive electrode comprising same

Patent metadata

Field	Value
Publication number	US-11955629-B2
Application number	US-201715757589-A
Country	US
Kind code	B2
Filing date	Mar 31, 2017
Priority date	Mar 31, 2016
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

Abstract

The present invention relates to a positive electrode active material having improved capacity characteristic and life cycle characteristic, and a method of preparing the same, and specifically, to a positive electrode active material for a lithium secondary battery, wherein the positive electrode active material comprises a compound represented by Formula 1 above and allowing reversible intercalation/deintercalation of lithium, and from a crystal structure analysis of the positive electrode active material by a Rietveld method in which space group R-3m is used in a crystal structure model on the basis of an X-ray diffraction analysis, the thickness of MO slab is 2.1275 Å or less, the thickness of inter slab is 2.59 Å or greater, and the cation mixing ratio between Li and Ni is 0.5% or less, and a method of preparing the same.

First claim

The invention claimed is:

1. A lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte,
wherein the positive electrode active material for a lithium secondary battery, the positive electrode active material consists of a compound represented by Formula 1 below and allowing reversible intercalation/deintercalation of lithium,
wherein from a crystal structure analysis of the positive electrode active material by a Rietveld method in which space group R-3m is used in a crystal structure model on the basis of an Xray diffraction analysis, a thickness of an MO slab is 2.1262 Å to 1270 Å, a thickness of an inter slab is 6051 Å to 6054 Å, and a cation mixing ratio between Li and Ni is from 0.30% to 0.36%,
wherein the cation mixing of Li and Ni refers to an amount of Ni cations present in a lithium layer,
Li x [Ni a1 Co b1 Mn c1 ]O 2   [Formula 1]

in Formula 1 above, 1.0≤x≤1.04, a1=0.88, b1=0.08, c1=0.04, and a1+b1+c1=1,
wherein a charging capacity of the lithium secondary battery is from 237.0 mAh/g to 237.2 mAh/g.

2. The lithium secondary battery of claim 1 , wherein a ratio of
inter slab/MO slab, which is the ratio between the thickness of the MO slab and the inter slab, is 1.2248 to 1.2253.

3. The lithium secondary battery of claim 1 , wherein a ratio of a c-axis to an a-axis (c/a) of the positive electrode active material is 9406 to 4.9413.

4. The lithium secondary battery of claim 1 , wherein an I(003/104) of the positive electrode active material is 2.0662 to 2.1242.

5. The lithium secondary battery of claim 1 , wherein an I(006+102)/(101) of the positive electrode active material is 0.7652 to 0.7720.

6. The lithium secondary battery of claim 1 , wherein a Z of the positive electrode active material is 0.24156 to 0.24158.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Jong Pil
• Cho Seung Beom
• Kim Won Tae
• Son San Su
• Lee Hyuck

Classifications

• H01M4/505 Primary

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• C01G53/50 Primary

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title