Positive electrode active material for secondary battery, and secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-2018261842-A1
Application number	US-201615760111-A
Country	US
Kind code	A1
Filing date	Nov 30, 2016
Priority date	Nov 30, 2015
Publication date	Sep 13, 2018
Grant date	—

Abstract

The present invention provides a positive electrode active material for a secondary battery, the positive electrode active material being a primary particle having a monolithic structure that includes a lithium composite metal oxide of Formula 1 below, wherein the primary particle has an average particle size (D 50 ) of 2 μm to 20 μm and a Brunauer-Emmett-Teller (BET) specific surface area of 0.15 m 2 /g to 1.9 m 2 /g, and a secondary battery including the same.

First claim

1 . A positive electrode active material for a secondary battery, the positive electrode active material being a primary particle having a monolithic structure that includes a lithium composite metal oxide of Formula 1 below,
wherein the primary particle has an average particle size (D 50 ) of 2 μm to 20 μm and a Brunauer-Emmett-Teller (BET) specific surface area of 0.15 m 2 /g to 1.9 m 2 /g:
Li a Ni 1-x-y Co x M1 y M3 z M2 w O 2   [Formula 1]

(In Formula 1, M1 is at least one selected from the group consisting of Al and Mn, M2 is any one or two or more elements selected from the group consisting of Zr, Ti, Mg, Ta, and Nb, M3 is any one or two or more elements selected from the group consisting of W, Mo, and Cr, and 1.0≤a≤1.5, 0≤x≤0.5, 0≤y≤0.5, 0.002≤z≤0.03, 0≤w≤0.04, 0<x+y≤0.7).

2 . The positive electrode active material of claim 1 , wherein in Formula 1, 0.4<x+y≤0.7.

3 . The positive electrode active material of claim 1 , wherein at least one metal element of nickel, M1, and cobalt exhibits a concentration gradient that changes in the active material.

4 . The positive electrode active material of claim 1 , wherein:
nickel, M1, and cobalt independently exhibit a concentration gradient that changes throughout the active material; the concentration of nickel decreases with a concentration gradient in a direction from a center of the active material to a surface thereof; and the concentrations of cobalt and M1 independently increases with a concentration gradient in the direction from the center of the active material to the surface thereof.

5 . The positive electrode active material of claim 1 , wherein the M1 is manganese (Mn).

6 . The positive electrode active material of claim 1 , wherein the positive electrode active material has a polyhedral shape.

7 . The positive electrode active material of claim 1 , wherein the positive electrode active material has a particle size distribution value (Dcnt), which is defined by Equation 1 below, of 0.5 to 1.0.
Dcnt=[Dn 90− Dn 10]/ Dn 50  [Equation 1]
(In Equation 1, Dn90, Dn10, and Dn50 are number average particle sizes measured under 90%, 10%, and 50%, respectively)

8 . The positive electrode active material of claim 1 , wherein the positive electrode active material has a rolling density of 3.0 g/cc or higher under a pressure of 2 ton·f.

9 . A method of fabricating the positive electrode active material for a secondary battery of claim 1 , the method comprising:
a step of preparing a precursor by mixing a nickel raw material, a cobalt raw material, and an M1 raw material (here, M1 is at least one element selected from the group consisting of Al and Mn) and then performing a reaction; a step of mixing the precursor with a lithium raw material and an M3 raw material (here, M3 is any one or two or more elements selected from the group consisting of W, Mo, and Cr) such that a molar ratio of Li/Me (Me=the sum of metal elements in the precursor and the element M3) is 2.0 or higher and then sintering at 700° C. to 900° C. in the presence of a boron-based sintering additive; and a step of washing a product obtained by a result of the sintering such that a molar ratio of Li/Me′ (Me′=the sum of metal elements, excluding lithium, in the positive electrode active material) in the finally fabricated positive electrode active material is from 1.0 to 1.5 and then drying at 150° C. to 400° C.

10 . The method of claim 9 , wherein an M2 raw material (M2 is any one or two or more elements selected from the group consisting of Zr, Ti, Mg, Ta, and Nb) is further added in the preparing of the precursor or the sintering.

11 . The method of claim 9 , wherein the precursor is fabricated by adding an ammonium cation-containing complexing agent and a basic compound to a metal-containing solution, which is produced by mixing the nickel raw material, the cobalt raw material, and the M1 raw material and performing a coprecipitation reaction.

12 . The method of claim 11 , wherein a second metal-containing solution including the nickel raw material, the cobalt raw material, and the M1 raw material in different concentrations from the metal-containing solution is further added to the metal-containing solution.

13 . The method of claim 9 , wherein the boron-based sintering additive includes any one or two or more selected from the group consisting of boric acid, lithium tetraborate, boron oxide, and ammonium borate.

14 . A positive electrode for a secondary battery, the positive electrode comprising the positive electrode active material of claim 1 .

15 . A lithium secondary battery comprising the positive electrode of claim 14 .

Assignees

• Lg Chemical Ltd

Inventors

• Park Byung Chun
• Jung Wang Mo
• Kang Seong Hoon
• Shin Ju Kyung
• Park Sang Min
• Lee Sang Wook

Classifications

• C01P2002/52

  containing elements as dopants · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• H01M4/505

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

• C01G53/50

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