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

Patent metadata

Field	Value
Publication number	US-2018241036-A1
Application number	US-201615754111-A
Country	US
Kind code	A1
Filing date	Nov 25, 2016
Priority date	Nov 30, 2015
Publication date	Aug 23, 2018
Grant date	—

Abstract

The present invention provides a positive electrode active material for a secondary battery, a positive electrode for a secondary battery, and a secondary battery including the same, the positive electrode active material including a first lithium-nickel oxide particle having an average particle size (D 50 ) of more than 8 μm to 20 μm or less, and a second lithium-nickel oxide particle having an average particle size (D 50 ) of 8 μm or less, wherein the first lithium-nickel oxide particle has a particle strength of 100 MPa to 250 MPa, the second lithium-nickel oxide particle has a particle strength of 50 MPa to 100 MPa, a ratio r of the strength of the first lithium-nickel oxide particle to the strength of the second lithium-nickel oxide particle satisfies Equation 1 set forth herein.

First claim

1 . A positive electrode active material for a secondary battery, the positive electrode active material comprising:
a first lithium-nickel oxide particle having an average particle size (D 50 ) of more than 8 μm to 20 μm or less; and a second lithium-nickel oxide particle having an average particle size (D 50 ) of 8 μm or less, wherein: the first lithium-nickel oxide particle has a particle strength of 100 MPa to 250 MPa, and the second lithium-nickel oxide particle has a particle strength of 50 MPa to 100 MPa; a ratio r of the strength of the first lithium-nickel oxide particle to the strength of the second lithium-nickel oxide particle satisfies Equation 1 below, and
1<r≤3  [Equation 1]

the first and second lithium-nickel oxides independently include nickel at a content of 80 atom % or more with respect to a total atomic weight of metal elements other than lithium present in the oxides.

2 . The positive electrode active material of claim 1 , wherein the first and second lithium-nickel oxide particles independently include a compound represented by Formula 1 below.
Li a Ni 1-x-y Co x M1 y M2 w O 2   [Formula 1]
(In Formula 1, 1.0≤a≤1.5, 0≤x≤0.2, 0≤y≤0.2, 0≤w≤0.1 and 0≤x+y≤0.2, M1 includes any one or both selected from the group consisting of Mn and Al, and M2 includes any one or two or more elements selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb, and Mo).

3 . The positive electrode active material of claim 2 , wherein, in Formula 1, 1.0≤a≤1.2, 0<x≤0.2, 0<y≤0.2, 0<w≤0.1 and 0<x+y≤0.2.

4 . The positive electrode active material of claim 1 , wherein nickel is distributed with a concentration gradient that gradually decreases from a particle center toward a particle surface in at least one particle of the first and second lithium-nickel oxide particles.

5 . The positive electrode active material of claim 1 , wherein a ratio of an average particle size of the first lithium-nickel oxide particle to an average particle size of the second lithium-nickel oxide particle (the average particle size of the first lithium-nickel oxide particle/the average particle size of the second lithium-nickel oxide particle) is 1.5 to 3.

6 . The positive electrode active material of claim 1 , wherein a tap density of the positive electrode active material is 2.0 g/cc or higher.

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

8 . The positive electrode of claim 7 , wherein:
the positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector; and the positive electrode active material layer includes the positive electrode active material at 90 to 98 wt % with respect to a total weight of the positive electrode active material layer.

9 . The positive electrode of claim 7 , wherein the positive electrode has an electrode density of 3.5 g/cc or higher.

10 . A lithium secondary battery comprising the positive electrode of claim 7 .

11 - 14 . (canceled)

Assignees

• Lg Chemical Ltd

Inventors

• Jo Chi Ho
• Park Sin Young
• Jung Wang Mo
• Park Byung Chun
• Baek So Ra

Classifications

• C01P2002/54

  one element only · CPC title

• H01M2004/021

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

• H01M4/362

  Composites · 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

• H01M10/0525

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