Positive electrode active material and preparation method thereof

Patent metadata

Field	Value
Publication number	US-9972841-B2
Application number	US-201515037218-A
Country	US
Kind code	B2
Filing date	Sep 25, 2015
Priority date	Sep 30, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

The present invention provides a positive electrode active material which includes a lithium transition metal oxide particle, composite particles, and at least one kind of conductive oxide particle on the lithium transition metal oxide particle surface, and also provides a preparation method for the positive electrode active material. The positive electrode active material includes lithium transition metal oxide particles and particular conductive oxide particles and composite particles which have a single phase, and thus the positive electrode active material not only has superb electronic conductivity, while having excellent ion transfer capability which allows transfer of metal ions such as lithium ions to lithium transition metal oxide particles, but may also minimize capacity reduction and output reduction in a secondary battery.

First claim

The invention claimed is:

1. A positive electrode active material, comprising:
lithium transition metal oxide particles;
conductive oxide particles; and
composite particles,
wherein the conductive oxide particles include antimony tin oxide (ATO) or a mixture of indium tin oxide (ITO) and ATO,
the conductive oxide particles and the composite particles are doped in the lithium transition metal oxide particles; or coated on the lithium transition metal oxide particles; or doped in and coated on the lithium transition metal oxide particles,
wherein the mixing ratio by weight of the conductive oxide particles to the composite particles is 1:0.01 to 1:1.5, and
the conductive oxide particles and the composite particles include a single-phase peak when measured by X-ray diffraction (XRD) analysis.

2. The positive electrode active material of claim 1 , wherein a coating layer which includes the conductive oxide particles and composite particles is formed on an outer surface of the lithium transition metal oxide particle.

3. The positive electrode active material of claim 2 , wherein the coating layer further comprises an oxide which includes one or more of calcium (Ca), niobium (Nb), tungsten (W), magnesium (Mg), titanium (Ti), boron (B), molybdenum (Mo), scandium (Sc), or zirconium (Zr).

4. The positive electrode active material of claim 2 , wherein the conductive oxide particles include those which have an average particle diameter of 1 nm to 100 nm.

5. The positive electrode active material of claim 1 , wherein the conductive oxide particles and composite particles are included in the interior of the lithium transition metal oxide particle, and thus have
concentration gradients in which the concentrations of the conductive oxide particles and composite particles decrease going from the surface of the lithium transition metal particle to the interior, and the conductive oxide particles and composite particles are composited with the lithium transition metal particle to form a composite material.

6. The positive electrode active material of claim 5 , wherein:
the concentrations of the conductive oxide particles and composite particles are at least about 20% higher in an exterior bulk of the lithium transition metal particle than in an interior bulk; and
the interior bulk is the center and adjacent regions of the lithium transition metal oxide particle, and includes about 50% of the total number of transition metal atoms which are in the particle.

7. The positive electrode active material of claim 5 , wherein the conductive oxide particles and composite particles are included, in a direction going from the surface of the particle to the interior, within a thickness range of about 0.0001 to about 80% of the particle radius.

8. The positive electrode active material of claim 1 , wherein:
a coating layer which includes the conductive oxide particles and composite particles is formed on an outer surface of the lithium transition metal oxide particle; and
the conductive oxide particles and composite particles are included in the interior of the lithium transition metal oxide particle, and thus have concentration gradients which decrease going from the surface to the interior, and are composited with the lithium transition metal particle to form a composite material.

9. The positive electrode active material of claim 8 , wherein the coating layer further comprises an oxide which includes one or more of calcium (Ca), niobium (Nb), tungsten (W), magnesium (Mg), titanium (Ti), boron (B), molybdenum (Mo), scandium (Sc), or zirconium (Zr).

10. The positive electrode active material of claim 8 , wherein the conductive oxide particles include those which have an average particle diameter of 1 nm to 100 nm.

11. The positive electrode active material of claim 1 , wherein the conductive oxide particles are included in an amount of 50 to 30000 ppm with respect to the entirety of the positive electrode active material.

12. The positive electrode active material of claim 1 , wherein the composite particle includes any one selected from a group which consists of yttria stabilized zirconia (YSZ), gadolinia-doped ceria (GDC), lanthanum strontium gallate magnesite (LSGM), lanthanum strontium manganite (LSM), Ca doped zirconia or calcia stabilized zirconia (CSZ), Sc doped zirconia (SSZ), and Ni—YSZ, or a mixture of at least two thereof.

13. The positive electrode active material of claim 12 , wherein oxygen vacancies are present in proportion to the amount of the element yttrium (Y).

14. The positive electrode active material of claim 12 , wherein the YSZ is Zr (1−x) Y x O 2−x/2 (0.01≤x≤0.30).

15. The positive electrode active material of claim 12 , wherein the conductive oxide particles include ATO and the composite particles include YSZ.

16. The positive electrode active material of claim 1 , wherein the conductive oxide is a mixed oxide of indium tin oxide and antimony tin oxide which are included at a weight ratio of 1:0.01 to 1:1.

17. The positive electrode active material of claim 1 , wherein the antimony tin oxide includes any one of compounds represented by the below Formula 1 or 2, or a mixture thereof:
(SnO 2 ) x (Sb 2 O 3 ) y   <Formula 1>

where, x and y satisfy x+y=1, 0<y/x≤2, 0.6≤x≤0.99, and 0.001≤y≤0.2; and
(SnO 2 ) x (Sb 2 O 5 ) y   <Formula 2>

where, x and y satisfy x+y=1, 0<y/x≤2, 0.6≤x≤0.99, and 0.001≤y≤0.2.

18. The positive electrode active material of claim 1 , wherein the indium tin oxide includes any one of compounds represented by the below Formula 3 or 4, or a mixture thereof:
(InO 2 ) a (SnO 2 ) b   <Formula 3>

where, a and b satisfy a+b=1, 0<b/a≤2, 0.6≤a≤0.99, and 0.001≤b≤0.2; and
(InO 2 ) a (SnO 2 ) b   <Formula 4>

where, a and b satisfy a+b=1, 0<b/a≤2, 0.6≤a≤0.99, and 0.001≤b≤0.2.

19. The positive electrode active material of claim 1 , wherein the lithium transition metal oxide particle includes the compound of Formula 5:
Li (1+a) Ni (1−b−c) Mn (b) CO (c) M′ (s) M″ (v) O 2   <Formula 5>

where,
M′ includes any one selected from among the group which consists of antimony (Sb), tin (Sn), indium (In), yttrium (Y), zirconium (Zr), lanthanum (La), strontium (Sr), gallium (Ga), magnesium (Mg), manganese (Mn), calcium (Ca), scandium (Sc), and nickel (Ni), or includes a mixed element of at least two thereof, or an oxide thereof;
M″ includes one or more element among calcium (Ca), niobium (Nb), tungsten (W), magnesium (Mg), titanium (Ti), boron (B), molybdenum (Mo), scandium (Sc), or zirconium (Zr), or oxides thereof; and
a, b, c, s, and v satisfy 0≤a<0.2, 0≤b≤0.5, 0≤c≤0.5, 0≤s≤0.2, and 0≤v≤0.2, respectively.

20. The positive electrode active material of claim 19 , wherein, in Formula 5, s and v have concentration gradients which decrease going from the surface of the lithium transition metal oxide particle to the interior.

21. The positive electrode active material of claim 1 , wherein the average particle diameter is 3 m to 30 μm.

22. The positive electrode active material of claim 1 , wherein the compressive strength is 10 to 500 MPa under pressure of 0.5 to 10 mN.

23. A method for preparing positive electrode active material of claim 1 , the method comprising:
mixing lithium transition metal oxide particles, conductive oxide particles, and composite particles; and
heat treating the mixed particles,
wherein the conductive oxide particles include antimony tin oxide (ATO) or a mixture of indium tin oxide (ITO) and ATO

Assignees

• Lg Chemical Ltd

Inventors

• Kwak Ick Soon
• Cho Seung Beom
• Yoon Yeo June

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/483 Primary

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M4/366

  as layered products · CPC title