Island-Covered Lithium Cobaltite Oxides

• US 20090309063A1
• Filed: 01/17/2008
• Published: 12/17/2009
• Est. Priority Date: 01/29/2007
• Status: Active Grant

• Current Assignee: Umicore S.A.
• Original Assignee: Umicore S.A.
• Inventors: Paulsen, Jens Martin, Lau, Thomas
• Granted Patent: US 8,785,042 B2
• Time in Patent Office: Days
• US Class Current: 252/182.330
• CPC Class Codes: C01G 45/1228 of the type [MnO2]n- , e.g. LiMnO2, Li[MxMn1-x]O2
• CPC Class Codes: C01G 51/42 containing alkali metals, e.g. LiCoO2
• CPC Class Codes: C01G 51/50 of the type [MnO2]n- , e.g. Li(CoxMn1-x)O2, Li(MyCoxMn1-x-y)O2
• CPC Class Codes: C01G 53/50 of the type [MnO2]n- , e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/77 by unit-cell parameters, atom positions or structure diagrams
• CPC Class Codes: C01P 2002/85 by XPS, EDX or EDAX data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2006/11 Powder tap density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries

Abstract

Disclosed is a cathode active material and a method to produce the same at low cost. The cathode powder comprises modified LiCoO₂, and possibly a second phase which is LiM′O₂ where M′is Mn, Ni, Co with a stoichiometric ratio Ni:Mn≧1. The modified LiCoO₂ is Ni and Mn bearing and has regions of low and high manganese content, where regions with high manganese content are located in islands on the surface. The cathode material has high cycling stability, a very high rate performance and good high temperature storage properties.

Claims

1-25. -25. (canceled)

26. A powderous lithium transition metal oxide comprising Mn and Ni bearing LiCoO₂ particles, said particles having Mn and Ni enriched islands on surfaces thereof, said islands having a Mn and Ni concentration that is higher than in the bulk of said particles, said islands comprising at least 5 mol % of Mn.

27. The powderous lithium transition metal oxide of claim 26, wherein said Mn and Ni enriched islands have a thickness of at least 100 nm and cover less than 70% of the surfaces of said Mn and Ni bearing LiCoO₂ particles.

28. The powderous lithium transition metal oxide of claim 26, wherein the Mn concentration in said islands is at least 4 mol % higher than the Mn concentration in the bulk of said Mn and Ni bearing LiCoO₂ particles.

29. The powderous lithium transition metal oxide of claim 26, wherein the Ni concentration in said Mn and Ni enriched islands is at least 2 mol % higher than the Ni concentration in the bulk of said Mn and Ni bearing LiCoO₂ particles.

30. The powderous lithium transition metal oxide of claim 26, having Mn and Ni bearing LiCoO₂ particles comprising at least 3 mol % of both Ni and Mn.

31. The powderous lithium transition metal oxide of claim 26, wherein crystallographic lattice constants a and c of said Mn and Ni bearing LiCoO₂ particles are respectively 2.815+/−

0.002 and 14.05+/−

0.01.

32. The powderous lithium transition metal oxide of claim 26, wherein the Mn and Ni bearing LiCoO₂ particles are monolithic and free of inner porosities.

33. The powderous lithium transition metal oxide of claim 26, wherein the size distribution of said Mn and Ni bearing LiCoO₂ particles has a d50 larger than 10 μ

m.

34. The powderous lithium transition metal oxide of claim 26, comprising between 30 wt. % and 95 wt. % of said Mn and Ni bearing LiCoO₂ particles.

35. The powderous lithium transition metal oxide of claim 26, comprising

a first phase consisting of said Mn and Ni bearing LiCoO₂ particles, and

a second island-free phase having a generalized formula of Li_1+aM′

_1-aO<sub>2±

b</sub>, with −

0.03<

a<

0.05 and b<

0.02, M′

Ni_mMn_nCo_1-m-n, with m≧

n, and 0.1<

m+n≦

0.9.

36. The powderous lithium transition metal oxide of claim 35, having a composition of Li_xM_yO_2±

δ

with;

0.97<

x<

1.03,0.97<

y<

1.03,x+y=2;

δ

<

0.05;

and M=Co_1-f-gNi_fMn_g, with 0.05<

f+g<

0.5 and f≧

g.

37. The powderous lithium transition metal oxide of claim 35, wherein crystallographic lattice constants a′

and c′

of said island-free phase have the following relationship with lattice constants a″ and

c″

of a corresponding island-free phase of a reference lithium transition metal (M_ref) oxide, having the same composition Li_xM_yO<sub>2±

δ</sub>

and consisiting of pure LiCoO₂ particles and said corresponding island-free phase;

0.980<

a′

/a″

<

0.998 and 0.9860<

c′

/c″

<

0.9985.

38. The powderous lithium transition metal oxide of claim 35, wherein said island-free phase has secondary particles having a size distribution with a d50 between 2 and 10 micrometer, said secondary particles consisting of sintered agglomerates of primary crystallites having a particle size distribution with a d50 between 0.5 and 2 μ

m.

39. The powderous lithium transition metal oxide of claim 35, wherein both said Mn and Ni enriched islands and said island-free phase further comprise Ti, wherein the Ti content is less than 10 mol % of M in the oxide Li_xM_yO_2±

δ

.

40. The powderous lithium transition metal oxide of claim 36, further comprising less than 5 mol % of M of one or more dopants selected from the group consisting of Al and Mg, and less than 1 mol % of M of one or more dopants selected from the group consisting of Be, B, Ca, Zr, S, F, and P.

41. An electrochemical cell comprising a cathode comprising as an active material the powderous lithium transition metal oxide of claim 26.

42. A method for preparing the powderous lithium transition metal oxide of claim 26, comprising:

providing a mixture of LiCoO₂ powder or a cobalt containing precursor compound having a cobalt content of at least 90 mol %, and a Li—

Ni—

Mn—

Co-oxide or a Ni—

Mn—

Co precursor powder and a Li-precursor compound; and

sintering said mixture at a temperature T of at least 910°

C. for a time t between 1 and 48 hrs;

to obtain Mn and Ni bearing LiCoO₂ particles having Mn and Ni enriched islands on surfaces thereof.

44. The method of claim 42, wherein the Ni—

Mn—

Co precursor powder comprises between 5 and 70 mol % of the transition metal content of said powderous lithium transition metal oxide.

45. The method of claim 42, wherein the LiCoO₂ powder has a tap density of at least 2 g/cm³, and consists of monolithic particles with a d50 of at least 10 μ

m.

46. The method of claim 42, wherein the cobalt containing precursor compound is selected from the group consisting of cobalt hydroxide, oxyhydroxide, carbonate, and mixtures thereof.

47. The method of claim 42, wherein said LiCoO₂ or cobalt containing precursor comprises at least 80% of the transition metal of said powderous lithium transition metal oxide, and the Ni—

Mn—

Co comprising precursor powder consists of particles having a particle size distribution with a d50 between 1 and 3 μ

m.

48. The method of claim 42, wherein said LiCoO₂ or cobalt containing precursor comprises less than 80% of the transition metal of said powderous lithium transition metal oxide, and the Ni—

Mn—

Co comprising precursor consists of particles of an agglomerated type having a particle size distribution with a d50 between 4 and 10 μ

m.

49. The method of claim 42, wherein the Ni—

Mn—

Co comprising precursor further comprises Ti, preferably in the form of TiO₂ particles with a d50 less than 100 nm.

43. The method of 42, wherein the Ni—

Mn—

Co precursor powder is a transition metal hydroxide, oxyhydroxide, carbonate, oxycarbonate, or lithium transition metal compound, wherein the transition metal composition M″

is M″

Ni_oMn_pCo_1-o-p, with o+p>

0.5 and o>

p.