Positive Electrode Active Material For Lithium Secondary Battery, And Positive Electrode Comprising Same

Patent metadata

Field	Value
Publication number	US-2022310996-A1
Application number	US-202217838392-A
Country	US
Kind code	A1
Filing date	Jun 13, 2022
Priority date	Mar 31, 2016
Publication date	Sep 29, 2022
Grant date	—

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

1 . A method of preparing a positive electrode active material for a lithium secondary battery comprising the steps of:
(Step 1) mixing a transition metal precursor represented by Formula 2 below and a lithium precursor such that the ratio of the number of moles of lithium present in the lithium precursor based on the total number of moles of transition metal present in the transition metal precursor (the number of moles of Li/the total number of moles of transition metal) is 1.03 or greater to prepare a mixture; and (Step 2) sintering the mixture at a temperature of 800° C. to 850° C. to form a compound represented by Formula 1 below and allowing reversible intercalation/deintercalation of lithium, and 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 X-ray diffraction analysis, a thickness of an MO slab is 2.126 Å to 2.1275 Å, a thickness of an inter slab is 2.59 Å to 2.615 Å, and a cation mixing ratio between Li and Ni is 0.5% or less:
Li x [Ni a1 Co b1 Mn c1 ]O 2   [Formula 1]

[Ni a2 Co b2 Mn c2 ](OH) 2   [Formula 2]

in the Formulas 1 and 2, 1.0≤x≤1.2, 0.85≤a1≤0.99, 0<b1<0.15, 0<c1<0.15, a1+b1+c1=1, 0.85≤a2≤0.99, 0<b2<0.15, 0<c2<0.15, and a2+b2+c2=1.

2 . The method of claim 1 , wherein the ratio of the number of moles of lithium present in the lithium precursor based on the total number of moles of transition metal present in the transition metal precursor (the number of moles of Li/the total number of moles of transition metal) is 1.03 to 1.04, in Step 1.

3 . The method of claim 1 , wherein the lithium precursor is at least one selected from the group consisting of Li 2 CO 3 , LiOH, LiOH.H 2 O, Li 2 O, and Li 2 O 2 .

4 . The method of claim 1 , further comprising heat-treating the mixture at a temperature of 500° C. to 600° C. prior to performing Step 2.

Assignees

• Lg Chemical Ltd

Inventors

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

Classifications

• H01M4/0471

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/505 Primary

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

• H01M4/1391

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

• C01P2002/78

  by stacking-plane distances or stacking sequences · CPC title