Electrode active material powder with size dependent composition and method to prepare the same

• US 7,771,877 B2
• Filed: 12/30/2004
• Issued: 08/10/2010
• Est. Priority Date: 12/31/2003
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Park, Hong Kyu, Paulsen, Jens Martin, Kim, Mun Ju
• Primary Examiner(s): Michener; Jennifer
• Assistant Examiner(s): WILLS, MONIQUE M
• Application Number:
  US10/584,992
• Publication Number:
  US 20070122705A1
• Time in Patent Office: 2,049 Days
• Field of Search: 429/231.95, 429/223, 429/231.3, 429/224, 429/231.5, 423/594.4, 423/594.6, 423/599
• US Class Current: 429/231.95
• 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 53/42 containing alkali metals, e.g. LiNiO2
• 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 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2002/88 by thermal analysis data, e.g. TGA, DTA, DSC
• CPC Class Codes: C01P 2004/03 obtained by SEM
• 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 2006/11 Powder tap density
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/366 as layered products
• 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

The present invention relates to a powderous electrode active material of lithium transition metal oxide LiaMbO2, wherein 0.9 < a < 1.1, 0.9 < b < 1.1 and M is dominantly transition metal chosen from Mn, Co and Nickel, having particles with a distribution of sizes, where the composition M varies with the size of the particles, and a preparation method thereof. The present invention also relates to an electrochemical cell, particularly rechargeable lithium battery, using the powderous electrode active material.

Claims

1. A powderous electrode active material comprising a lithium transition metal oxide Li_aM_bO₂ ,

where 0.9<

a <

1.1, 0.9<

b <

1.1 and M is a mixture of at least two transition metals selected from the group consisting of Mn, Co and Ni,

said material having particles with a distribution of sizes,

where the content of Mn, Co and Ni in M varies with the size of the particles.

2. The powderous electrode active material according to claim 1, having a broad particle size distribution specified that the size ratio of large to small particles exceeds 2, d90/d10>

2 where d90, the size of large particles is defined that particles with larger size constitute a fraction of 10% of the total mass of the powder and d10, the size of small particles is defined that particles with smaller size constitute a fraction of 10% of the total mass of the powder.

3. The powderous electrode active material according to claim 1, where M =A_zA′

_z′

M′

<sub>1−

z−

z′</sub>

, M′

=Mn_xNi_yCo<sub>1−

x−

y</sub>, 0≦

y≦

1, 0≦

x≦

1, 0≦

z+z′

<

0.1, z′

<

0.02, A is a metal chosen from Al, Mg, Ti, Cr and A′

is a further minor dopant chosen from F, Cl, S, Zr, Ba, Y, Ca, B, Be, Sn, Sb, Na, Zn.

4. The powderous electrode active material according to claim 1, wherein the particles have a layered crystal structure.

8. The powderous electrode active electrode active material of Li_aM_bO₂ with size dependent composition according to claim 1, where basically all bulk of all particles has a layered crystal structure, larger particles having a composition Li_aM_bO₂ where M=Mn_xNi_y(Co₁₋

x−

y) with x+y<

0.35 and smaller particles having a different composition Li_aM_bO₂ where M=Mn_x′

Ni_y′

(Co<sub>1−

x′

−

y′</sub>

) with at least 10% less cobalt (1−

x′

−

y′

)<

0.9*(1−

x−

y) and at least 5% more manganese x′

−

x>

0.05.

9. The powderous electrode active material according to claim 8, wherein larger particles, specified by having a size larger than d50—

these larger particles comprise a mass fraction exceeding 50% of the total mass of the powder—

have a different composition in the inner bulk and the outer bulk.

10. The powderous electrode active material according to claim 9, wherein the inner bulk of larger particles has a composition Li_aM_bO₂ where M=Mn_xNi_y(Co₁₋

x−

y) and x<

0.2.

11. The powderous electrode active material according to claim 9, wherein the inner bulk of larger particles has a composition Li_aM_bO₂ where M=Mn_xNi_yCo₁₋

x−

y with x+y<

0.2.

12. The powderous electrode active material according to claim 9, wherein the inner bulk of larger particles has a higher stoichiometry of cobalt and a lower stoichiometry of manganese than the outer bulk.

15. The powderous electrode active material according to claim 12, wherein the inner bulk of larger particles has a composition Li_aM_bO₂ where M=Mn_xNi_y(Co₁₋

x−

y) and x<

0.2.

19. The powderous electrode active material according to claim 1, where the Co stoichiometry of single particles continuously increases with the particle size.

20. The powderous electrode active material according to claim 1, where the Mn stoichiometry of single particles continuously decreases with the particle size.

21. The powderous electrode active material according to claim 20, wherein the manganese stoichiometry is proportional to the inverse of the radius of the particle.

25. The powderous material according to claim 1, which is used as cathode active material in a rechargeable lithium batteries.

27. A method for preparing the powderous electrode active material of claim 1, the method comprising the steps of:

precipitating at least one transition metal containing precipitate onto seed particles, which have a different transition metal composition than the precipitate;

adding a controlled amount of a source of lithium; and

performing at least one heat treatment.

wherein basically all obtained particles contain a core, originating from a seed, completely covered by a layer originating from precipitate.

28. The method according to claim 27, wherein the precipitate contains manganese, and the seeds dominantly are monolithic particles chosen from LiCoO₂ or LiMO₂ where M is transition metal M=Mn_xNi_yCo₁₋

x−

y, where x<

0.25 and y<

0.9.

29. The method according to claim 28, wherein at least 40 w % of the transition metal of the precipitate is manganese.

30. The method according to claim 28, wherein the outer layer originating from the precipitate contains further at least one metal element chosen from Al, Mg, Ti, Zr, Sn, Ca and Zn.

31. The method according to claim 27, wherein the heat treatment is made in air, the temperature being within the range from 750 to 1050°

C.

5. A powderous electrode active material comprising lithium transition metal oxide Li_aM_bO₂,

where 0.9<

a <

1.1, 0.9<

b <

1.1 and M is a mixture of at least two transition metals selected from the group consisting of Mn, Co and Ni,

said material having particles with a layered crystal structure, and

having a broad particle size distribution with d90/d10>

2,

where the content of Mn, Co, and Ni in M varies with the size of the particles.

6. The powderous electrode active material of Li_aM_bO₂ with size dependent composition according to claim 5, wherein the averaged transition metal composition is M=Mn_xNi_y(Co₁₋

x−

y) with 0.35>

x>

0.03.

7. The powderous electrode active electrode active material of Li_aM_bO₂ with size dependent composition according to claim 5, wherein the averaged transition metal composition is M=Mn_xNi_y(Co₁₋

x−

y) with x>

0.03 and x+y<

0.7.

13. The powderous electrode active material of Li_aM_bO₂ with size dependent composition according to 5, where basically all bulk of all particles has a layered crystal structure, larger particles having a composition Li_aM_bO₂ where M=Mn_xNi_y(Co₁₋

x−

y) with x+y<

0.35 and smaller particles having a different composition Li_aM_bO₂ where M=Mn_x′

Ni_y′

(Co<sub>1−

x′

y′</sub>

) with at least 10% less cobalt (1−

x′

−

y′

)<

0.9*(1−

x−

y) and at least 5% more manganese x′

−

x>

0.05.

14. The powderous electrode active material according to claim 13, wherein larger particles, specified by having a size larger than d50—

these larger particles comprise a mass fraction exceeding 50% of the total mass of the powder—

have a different composition in the inner bulk and the outer bulk.

16. The powderous electrode active material according to claim 14, wherein the inner bulk of larger particles has a composition Li_aM_bO₂ where M=Mn_xNi_yCo₁₋

x−

y with x+y<

0.2.

17. The powderous electrode active material according to claim 14, wherein the inner bulk of larger particles has a higher stoichiometry of cobalt and a lower stoichiometry of manganese than the outer bulk.

18. The powderous electrode active material according to claim 5, wherein the composition M varies continuously with the size of the particles.

22. The powderous electrode active material according to claim 5, where the Co stoichiometry of single particles continuously increases with the particle size.

23. The powderous electrode active material according to claim 5, where the Mn stoichiometry of single particles continuously decreases with the particle size.

24. The powderous electrode active material according to claim 23, wherein the manganese stoichiometry is proportional to the inverse of the radius of the particle.

26. The powderous material according to claim 5, which is used as cathode active material in a rechargeable lithium batteries.

32. A method for preparing the powderous electrode active material of claim 5, the method comprising the steps of:

precipitating at least one transition metal containing precipitate onto seed particles, which have a different transition metal composition than the precipitate;

adding a controlled amount of a source of lithium; and

performing at least one heat treatment.

wherein basically all obtained particles contain a core, originating from a seed, completely covered by a layer originating from precipitate.

33. The method according to claim 32, wherein the precipitate contains manganese, and the seeds dominantly are monolithic particles chosen from LiCoO₂ or LiMO₂ where M is transition metal M=Mn_xNi_yCo₁₋

x−

y where x<

0.25 and y<

0.9.

34. The method according to claim 33, wherein at least 40 w % of the transition metal of the precipitate is manganese.

35. The method according to claim 33, wherein the outer layer originating from the precipitate contains further at least one metal element chosen from Al, Mg, Ti, Zr, Sn, Ca and Zn.

36. The method according to claim 32, wherein the heat treatment is made in air, the temperature being within the range from 750 to 1050°

C.