Lithium Cobalt Oxide Based Compounds with a Cubic Secondary Phase

Patent metadata

Field	Value
Publication number	US-2016268601-A1
Application number	US-201615064669-A
Country	US
Kind code	A1
Filing date	Mar 9, 2016
Priority date	Jun 17, 2011
Publication date	Sep 15, 2016
Grant date	—

Abstract

A lithium metal oxide powder for a cathode material in a rechargeable battery, comprising a core material and a surface layer, the core having a layered crystal structure consisting of the elements Li, a metal M and oxygen, wherein the metal M has the formula M=Co 1-a M′ a , with 0≦a≦0.05, wherein M′ is selected from one or more metals of the group consisting of Al, Ga and B; and the surface layer comprising a mixture of the elements of the core material Li, M and oxygen, inorganic N-based oxides and a cubic phase oxide having a crystal structure with a Fd-3mS space group, wherein N is selected from one or more metals of the group consisting of Mg, Ti, Fe, Cu, Ca, Ba, Y, Sn, Sb, Na, Zn, Zr and Si.

First claim

1 . A lithium metal oxide powder for a cathode material in a rechargeable battery, comprising a core material and a surface layer, the core having a layered crystal structure consisting of the elements Li, a metal M and oxygen, wherein the metal M has the formula M=Co 1-a M′ a , with 0≦a≦0.05, wherein M′ is selected from one or more metals of the group consisting of Al, Ga and B; and the surface layer comprising a mixture of the elements of the core material Li, M and oxygen, inorganic N-based oxides and a cubic phase oxide having a crystal structure with a Fd-3mS space group, wherein N is selected from one or more metals of the group consisting of Mg, Ti, Fe, Cu, Ca, Ba, Y, Sn, Sb, Na, Zn, Zr and Si.

2 . The lithium metal oxide powder of claim 1 , wherein the Li content is set at a value of Li:M of 0.995 or below.

3 . The lithium metal oxide powder of claim 2 , wherein the Li content is set at a value of Li:M between 0.963 and 0.993.

4 . The lithium metal oxide powder of claim 1 , wherein the cubic phase oxide having a crystal structure with a Fd-3mS space group has a lattice constant “a s ” with 8.055≦a s ≦8.150, a c and a s being expressed in Å.

5 . The lithium metal oxide powder of claim 1 , wherein the amount of cubic phase oxide in the powder is between 0.1 and 5 wt %.

6 . The lithium metal oxide powder of claim 1 , wherein the powder has an electrical conductivity less than 10 −5 S/cm, the electrical conductivity being measured under an applied pressure of 63.7 MPa.

7 . The lithium metal oxide powder of claim 1 , having a 7 Li MAS NMR spectrum that features a unique resonance around −0.5 ppm.

8 . The lithium metal oxide powder of claim 1 , wherein 0<a≦0.03.

9 . The lithium metal oxide powder of claim 1 , wherein the thickness of the surface layer is less than 100 nm.

10 . The lithium metal oxide powder claim 1 , wherein N consists of Mg and Ti, the Mg content being between 0.1 and 1 mol % and the Ti content between 0.1 and 0.5 mol %.

11 . The lithium metal oxide powder claim 1 , wherein the N-based oxides comprise oxides having incorporated Li atoms.

12 . The lithium metal based powder of claim 1 , wherein the core material is substantially free from the paramagnetic metals Co 2+ , intermediate spin Co 3+ and Co 4+ .

13 . The lithium metal oxide powder of claim 1 , wherein the powder has a bimodal particle shape distribution where the small particle size fraction has a D50≦5 μm and is between 3 to 20 Vol %, and where the large particle size fraction has a D50≧12 μm.

14 . The lithium metal oxide powder of claim 1 , wherein a concentration of N in the surface layer decreases with increasing distance from the surface of the lithium metal oxide powder.

15 . A method for manufacturing a lithium metal oxide powder for a cathode material in a rechargeable battery, the powder comprising a core material and a surface layer, the core having a layered crystal structure consisting of the elements Li, a metal M and oxygen, wherein the metal M has the formula M=Co 1-a M′ a , with 0≦a≦0.05, wherein M′ is selected from one or more metals of the group consisting of Al, Ga and B; and the surface layer comprising a mixture of the elements of the core material Li, M and oxygen, inorganic N-based oxides and a cubic phase oxide having a crystal structure with a Fd-3mS space, wherein N is selected from one or more metals of the group consisting of Mg, Ti, Fe, Cu, Ca, Ba, Y, Sn, Sb, Na, Zn, Zr and Si, the method comprising:
providing a first mixture of a first Co- or Co and M′-comprising precursor powder and a first Li-comprising precursor powder, the first mixture having a Li to M molar ratio>1.01,
sintering the first mixture in an oxygen comprising atmosphere at a temperature T 1 of at least 600° C., thereby obtaining a Li-enriched lithium metal oxide compound,
providing a second Co- or Co and M′-comprising precursor powder, and
mixing the Li-enriched lithium metal oxide compound and the second Co- or Co and M′-comprising precursor powder, thereby obtaining a second mixture wherein the molar ratio of Li to M is ≦0.995, and
sintering the second mixture in an oxygen comprising atmosphere at a temperature T 2 of at least 600° C.;
wherein one or more of the first Co- or Co and M′-comprising precursor powder, the first Li-comprising precursor powder, or the second Co- or Co and M′-comprising precursor powders further comprises at least one element selected from the group consisting of Mg, Ti, Fe, Cu, Ca, Ba, Y, Sn, Sb, Na, Zn, Zr and Si.

16 . The method according to claim 15 , wherein the first mixture has a Li to M molar ratio between 1.02 and 1.12.

17 . The method according to claim 15 , wherein the second mixture has a ratio of Li to metal Li:M between 0.963 and 0.993.

18 . An electrochemical cell comprising a cathode comprising the lithium metal oxide powder according to claim 1 .

Assignees

• Umicore Nv

Inventors

• Paulsen Jens
• Blangero Maxime
• Choi Da-In

Classifications

• C01P2006/12

  Surface area · CPC title

• C01G51/42

  containing alkali metals, e.g. LiCoO2 · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• H01M4/366

  as layered products · CPC title