Positive electrode active materials for secondary batteries and methods of preparing same

• US 6,878,490 B2
• Filed: 10/29/2001
• Issued: 04/12/2005
• Est. Priority Date: 08/20/2001
• Status: Expired due to Term

• Current Assignee: Umicore S.A.
• Original Assignee: FMC Corporation
• Inventors: Leonowicz, Michael E., Gao, Yuan, Yakovleva, Marina, Engel, John F., Palepu, Prakash
• Primary Examiner(s): Kalafut, Stephen J.
• Application Number:
  US10/040,047
• Publication Number:
  US 20030035999A1
• Time in Patent Office: 1,261 Days
• Field of Search: 429/209, 429/218.1, 429/221, 429/223, 429/231.1, 429/231.3, 429/231.5, 429/232, 252/182.1, 423/594.2, 423/594.4, 423/594.6, 423/594.12, 423/598
• US Class Current: 429/231.1
• CPC Class Codes: C01G 23/005 Alkali titanates
• CPC Class Codes: C01G 53/42 containing alkali metals, e.g. LiNiO2
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/74 by peak-intensities or a ratio thereof only
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• 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: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention is a positive electrode active material that can be used in secondary lithium and lithium-ion batteries to provide the power capability, i.e., the ability to deliver or retake energy in short periods of time, desired for large power applications such as power tools, electric bikes and hybrid electric vehicles. The positive electrode active material of the invention includes at least one electron conducting compound of the formula LiM¹_x−y{A}_yO_z and at least one electron insulating and lithium ion conducting lithium metal oxide, wherein M¹ is a transition metal, {A} is represented by the formula Σw_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σw_i=1; B_i is a cation in LiM¹_x−y{A}_yO_z; 0.95≦x≦2.10; 0≦y≦x/2; and 1.90≦z≦4.20. Preferably, the lithium metal oxide is LiAlO₂ or Li₂M²O₃ wherein M² is at least one tetravalent metal selected from the group consisting of Ti, Zr, Sn, Mn, Mo, Si, Ge, Hf, Ru and Te. The present invention also includes methods of making this positive electrode active material.

Claims

1. A positive electrode active material for secondary lithium and lithium-ion batteries comprising:

at least one electron conducting compound existing in a first single phase having the formula LiM¹<sub>x−

y</sub>{A}_yO_z wherein M¹ is a transition metal;

{A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0.95≦

x≦

1.05;

0≦

y≦

x/2; and

1.90≦

z≦

2.10; and

at least one electron insulating and lithium ion conducting lithium metal oxide Li₂M²O₃ existing in a second single phase structurally separate from the first single phase of the compound having the formula LiM¹<sub>x−

y</sub>{A}_yO_z, wherein M² is at least one tetravalent metal selected from the group consisting of Ti, Zr, and Hf.

2. The positive electrode active material according to claim 1, wherein the lithium metal oxide is selected from the group consisting of Li₂TiO₃, Li₂ZrO₃ and mixtures thereof.

3. The positive electrode active material according to claim 1, wherein the lithium metal oxide is Li₂TiO₃.

4. The positive electrode active material according to claim 1, comprising from greater than or equal to 95% by weight and less than 100% by weight of LiM¹_x−

y{A}_yO_z and greater than 0% by weight and less than or equal to 5% by weight of the lithium metal oxide.

5. The positive electrode active material according to claim 1, wherein M¹ is selected from the group consisting of Co, Ni, and Fe.

6. The positive electrode active material according to claim 1, wherein x=1 and z=2.

7. The positive electrode active material according to claim 6, wherein M¹ is Ni.

8. The positive electrode active material according to claim 6, wherein M¹ is Co.

9. The positive electrode active material according to claim 1, wherein y>

0.

10. The positive electrode active material according to claim 9, wherein the dopant elements B_i are selected from the group consisting of elements having a Pauling'"'"'s electronegativity not greater than 2.05.

11. The positive electrode active material according to claim 9, wherein the dopant elements B_i include two or more dopant cations.

12. The positive electrode active material according to claim 11, wherein the average oxidation state E of the dopant elements B_i, as determined using the formula E=Σ

w_iE_i wherein E_i is the oxidation state of dopant element B_i in the lithium metal oxide LiM¹<sub>x−

y</sub>{A}_yO_z, is represented by the relationship 2.5≦

E≦

3.5.

13. The positive electrode active material according to claim 12, wherein 2.9≦

E≦

3.1.

14. The positive electrode active material according to claim 12, wherein E=3.

15. The positive electrode active material according to claim 11, wherein at least one of the dopant elements B_i has a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

16. The positive electrode active material according to claim 11, wherein at least two of the dopant elements B_i have a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

17. The positive electrode active material according to claim 1, wherein x, y and z are values that provide a stable lithium metal oxide compound.

18. The positive electrode active material according to claim 1, wherein the metal M² is present in LiM¹_x−

y{A}_yO_z as a dopant element B_i.

19. The positive electrode active material according to claim 18, wherein the lithium metal oxide has the formula Li₂M²O₃ and M² includes Ti.

20. The positive electrode active material according to claim 1, wherein M¹ is Ni or Co, M² is Ti, and the dopant elements B_i include Ti⁴⁺.

21. The positive electrode active material according to claim 20, wherein M¹ is Ni.

22. The positive electrode active material according to claim 1, further comprising at least one electron insulating and lithium-ion conducting metal oxide.

26. A positive electrode for a secondary lithium or lithium-ion battery comprising the positive electrode active material of claim 1, a carbonaceous material and a polymer binder.

27. A secondary lithium or lithium-ion battery comprising a positive electrode, a negative electrode and a nonaqueous electrolyte, wherein the positive electrode includes the positive electrode active material of claim 1.

23. A positive electrode active material for secondary lithium and lithium-ion batteries comprising:

at least one electron conducting compound having the formula LiM¹<sub>x−

y</sub>{A}_yO_z wherein M¹ is a transition metal;

{A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0.95≦

x≦

1.05;

0≦

y≦

x/2; and

1.90≦

z≦

2.10;

at least one electron insulating and lithium ion conducting lithium metal oxide Li₂M²O₃, wherein M² is at least one tetravalent metal selected from the group consisting of Ti, Zr, and Hf; and

at least one electron insulating and lithium-ion conducting metal oxide, wherein the metal oxide has the formula MO₂ wherein M is at least one tetravalent metal selected from the group consisting of Ti, Zr, Mo, Si, Ge, Hf, Ru and Te.

24. The positive electrode active material according to claim 23, wherein M=M².

25. The positive electrode active material according to claim 24, wherein said metal oxide is TiO₂.

28. A positive electrode active material for secondary lithium and lithium-ion batteries comprising at least one compound existing in a first single phase having the formula LiM¹_x−

y{A}_yO_z and at least one lithium metal oxide of the formula Li₂M²O₃, existing in a second single phase structurally separate from the first single phase of the compound having the formula LiM¹<sub>x−

y</sub>{A}_yO_z;

wherein M¹ is a transition metal, M² is at least one tetravalent metal {A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0.95≦

x≦

2.10;

0≦

y≦

x/2; and

1.90≦

z≦

4.20.

29. The positive electrode active material according to claim 28, wherein the lithium metal oxide is selected from the group consisting of Li₂TiO₃, Li₂ZrO₃ and mixtures thereof.

30. The positive electrode active material according to claim 29, wherein the lithium metal oxide is Li₂TiO₃.

31. The positive electrode active material according to claim 28, comprising from greater than or equal to 95% by weight and less than 100% by weight of LiM¹_x−

y{A}_yO_z and greater than 0% by weight and less than or equal to 5% by weight of the lithium metal oxide.

32. The positive electrode active material according to claim 28, wherein x=1 and z=2.

34. The positive electrode active material according to claim 28, wherein M¹ is selected from Co, Ni, and Fe.

35. The positive electrode active material according to claim 28, wherein y>

0.

36. The positive electrode active material according to claim 35, wherein the dopant elements B_i are selected from the group consisting of elements having a Pauling'"'"'s electronegativity not greater than 2.05.

37. The positive electrode active material according to claim 35, wherein the dopant elements B_i includes two or more dopant cations.

38. The positive electrode active material according to claim 37, wherein the average oxidation state E of the dopant elements B_i, as determined using the formula E=Σ

w_iE_i wherein E_i is the oxidation state of dopant element B_i in the lithium metal oxide LiM¹<sub>x−

y</sub>{A}_yO_z, equals the oxidation state of the replaced transition metal ion M¹±

0.5.

39. The positive electrode active material according to claim 38, wherein E equals the oxidation state of the replaced transition metal ion M¹±

0.1.

40. The positive electrode active material according to claim 38, wherein E equals the oxidation state of the replaced transition metal ion M¹.

41. The positive electrode active material according to claim 37, wherein at least one of the dopant elements B_i has a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

42. The positive electrode active material according to claim 37, wherein at least two of the dopant elements B_i have a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

43. The positive electrode active material according to claim 28, wherein x, y and z are values that provide a stable lithium metal oxide compound.

44. The positive electrode active material according to claim 28, wherein the lithium metal oxide has the formula Li₂M²O₃ and M² includes Ti.

45. The positive electrode active material according to claim 28, further comprising at least one electron insulating and lithium ion conducting metal oxide.

49. A positive electrode for a secondary lithium or lithium-ion battery comprising the positive electrode active material of claim 28, a carbonaceous material and a binder polymer.

50. A secondary lithium or lithium-ion battery comprising a positive electrode, a negative electrode and a nonaqueous electrolyte, wherein the positive electrode includes the positive electrode active material of claim 28.

33. A positive electrode active material for secondary lithium and lithium-ion batteries comprising at least one compound of the formula LiM¹_x−

y{A}_yO_z and at least one lithium metal oxide of the formula Li₂M²O₃, wherein M¹ is a transition metal, M² is at least one tetravalent metal {A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0≦

y≦

1;

x=2; and

z=4.

46. A positive electrode active material for secondary lithium and lithium-ion batteries comprising:

at least one compound of the formula LiM¹<sub>x−

y</sub>{A}_yO_z and at least one lithium metal oxide of the formula Li₂M²O₃, wherein M¹ is a transition metal, M² is at least one tetravalent metal, {A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0.95≦

x≦

2.10;

0≦

y≦

x/2; and

1.90≦

z≦

4.20; and

at least one electron insulating and lithium ion conducting metal oxide, wherein the metal oxide has the formula MO₂ wherein M is at least one tetravalent metal selected from the group consisting of Ti, Zr, Mo, Si, Ge, Hf, Ru and Te.

47. The positive electrode active material according to claim 46, wherein M=M².

48. The positive electrode active material according to claim 46, wherein said metal oxide is TiO₂.

51. A method of preparing a positive electrode active material for secondary lithium and lithium-ion batteries, the positive electrode active material including separate lithium metal oxide phases corresponding to the formulae LiM¹_x−

y{A}_yO_z and Li₂M²O₃ comprising the steps of;

intimately mixing source compounds containing M¹, Li and optionally {A} in amounts sufficient to provide a stoichiometric relationship between M¹, Li and {A} corresponding to the formula LiM¹<sub>x−

y</sub>{A}_yO_z wherein M¹ is a transition metal, {A} is represented by the formula Σ

w_iB_i wherein B_i is an element other than M¹ used to replace the transition metal M¹ and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1;

B_i is a cation in LiM¹<sub>x−

y</sub>{A}_yO_z;

0.95≦

x≦

2.10;

0≦

y≦

x/2; and

1.90≦

z≦

4.20;

firing the mixture in the presence of oxygen at an initial firing temperature and optionally one or more additional firing temperatures, at least one of said initial firing temperature and optionally one or more additional firing temperatures being the maximum firing temperature and at least one of said initial firing temperature and optionally one or more additional firing temperatures being between about 700°

C. and about 1000°

C., wherein said firing step comprises heating the mixture at a sufficiently slow rate from 500°

C. to the maximum firing temperature to produce separate lithium metal oxide phases including LiM¹<sub>x−

y</sub>{A}_yO_z and Li₂M²O₃, wherein M² is one of M¹ and B_i; and

cooling the LiM¹<sub>x−

y</sub>{A}_yO_z and Li₂M²O₃ compounds.

52. The method according to claim 51, wherein said firing step comprises heating the mixture from 500°

C. to the maximum firing temperature at an average rate of less than or equal to about 10°

C./min.

53. The method according to claim 51, wherein said firing step comprises heating the mixture at a sufficiently slow rate from 500°

C. to the maximum firing temperature to produce separate lithium metal oxide phases including LiM¹<sub>x−

y</sub>{A}_yO_z, Li₂M²O₃ and M²O₂, wherein one of M¹ and B_i is M² and M² is selected from the group consisting of Ti, Zr, and Hf.

54. The method according to claim 51, wherein said mixing step comprises dry mixing the source compounds.

55. The method according to claim 51, wherein said mixing step comprises preparing a solution comprising M¹ and {A} from source compounds comprising M¹ and {A}, precipitating the M¹ and {A} out of solution to produce an intimately mixed hydroxide and blending the mixed hydroxide with a lithium source compound.

56. The method according to claim 51, wherein said firing step comprises firing the mixture at a partial pressure of oxygen of at least 20 kPa.

57. The method according to claim 51, wherein said firing step comprises heating the mixture at a sufficiently slow rate from 500°

C. to the maximum firing temperature to produce separate lithium metal oxide phases including LiM¹<sub>x−

y</sub>{A}_yO_z and Li₂M²O₃ such that the lithium metal oxide phases include greater than or equal to 95% by weight and less than 100% by weight of LiM¹<sub>x−

y</sub>{A}_yO_z and greater than 0% by weight and less than or equal to 5% by weight of Li₂M²O₃.

58. The method according to claim 51, wherein said mixing step comprises mixing source compounds containing a transition metal M¹ selected from the group consisting of Co, Ni, and Fe.

59. The method according to claim 51, wherein said mixing step comprises mixing source compounds including dopant elements B_i such that y>

0.

60. The method according to claim 59, wherein said mixing step comprises mixing source compounds including dopant elements B_i selected from the group consisting of elements having a Pauling'"'"'s electronegativity not greater than 2.05.

61. The method according to claim 59, wherein said mixing step comprises mixing source compounds including two or more dopant elements B_i.

62. The method according to claim 61, wherein said mixing step comprises mixing source compounds wherein the average oxidation state E of the dopant elements B_i, as determined using the formula E=Σ

w_iE_i wherein E_i is the oxidation state of dopant element B_i in the lithium metal oxide LiM¹<sub>x−

y</sub>{A}_yO_z, equals the oxidation state of the replaced transition metal ion M¹±

0.5.

63. The method according to claim 61, wherein said mixing step comprises mixing source compounds wherein the average oxidation state E of the dopant elements B_i, as determined using the formula E=Σ

w_iE_i wherein E_i is the oxidation state of dopant element B_i in the lithium metal oxide LiM¹<sub>x−

y</sub>{A}_yO_z equals the oxidation state of the replaced transition metal ion M¹±

0.1.

64. The method according to claim 61, wherein said mixing step comprises mixing source compounds wherein the average oxidation state E of the dopant elements B_i, as determined using the formula E=Σ

w_iE_i wherein E_i is the oxidation state of dopant element B_i in the lithium metal oxide LiM¹<sub>x−

y</sub>{A}_yO_z, equals the oxidation state of the replaced transition metal ion M¹.

65. The method according to claim 61, wherein said mixing step comprises mixing source compounds wherein at least one of the dopant elements B_i has a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

66. The method according to claim 61, wherein said mixing step comprises mixing source compounds wherein at least two of the dopant elements B_i has a different oxidation state than M¹ in LiM¹_x−

y{A}_yO_z.

67. The method according to claim 61, wherein said mixing step comprises mixing source compounds in amounts sufficient to provide values for x, y and z that provide a stable metal oxide compound.

68. The method according to claim 51, wherein said mixing step comprises mixing the source compounds in amounts sufficient to produce a LiM¹_x−

y{A}_yO_z compound wherein x=1 and z=2.

69. The method according to claim 68, wherein said mixing step comprises mixing source compounds containing Ni or Co as the transition metal M¹.

70. The method according to claim 69, wherein said mixing step comprises mixing source compounds containing Ti⁴⁺ as a dopant element B_i.

71. The method according to claim 70, wherein said mixing step comprises mixing source compounds containing Ni as the transition metal M¹.

72. The method according to claim 69, wherein said mixing step comprises mixing source compounds containing Co as the transition metal M¹.

73. The method according to claim 51, wherein said mixing step comprises mixing source compounds containing Li, Ni, Co, M³ and M⁴ in amounts sufficient to provide a stoichiometric relationship between Li, Ni, Co, M³ and M⁴ corresponding to the formula LiNi₁₋

yCo_aM³_bM⁴_cO₂ wherein M³ is selected from the group consisting of Ti, Zr, and combinations thereof;

M⁴ is selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof;

M² is M³;

y=a+b+c, 0<

y≦

0.5;

0<

a<

0.5;

0<

b≦

0.15; and

0<

c≦

0.15.

74. The method according to claim 51, wherein said mixing step comprises mixing the source compounds in amounts sufficient to produce a LiM¹_x−

y{A}_yO_z compound wherein x=2 and z=4.

75. The method according to claim 51, wherein said cooling step comprises cooling the LiM¹_x−

y{A}_yO_z and Li₂M²O₃ compounds at a rate of greater than or equal to about 0.5°

C./min and less than or equal to about 140°

C./min.

76. The method according to claim 51, wherein said mixing step comprises mixing source compounds such that excess of the source compound containing lithium is provided in the mixture.

77. A method of preparing a positive electrode active material for secondary lithium and lithium-ion batteries, the positive electrode active material including separate lithium metal oxide phases corresponding to the formulae LiNi₁₋

yCo_aM³_bM⁴_cO₂ and Li₂M³O₃ comprising the steps of;

intimately mixing source compounds containing Li, Ni, Co, M³ and M⁴ in amounts sufficient to provide a stoichiometric relationship between Li, Ni, Co, M³ and M⁴ corresponding to the formula LiNi<sub>1−

y</sub>Co_aM³_bM⁴_cO₂ wherein M³ is selected from the group consisting of Ti, Zr and combinations thereof;

M⁴ is selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof;

y=a+b+c, 0<

y≦

0.5;

0<

a<

0.5;

0<

b≦

0.15; and

0<

c≦

0.15;

firing the mixture in the presence of oxygen at an initial firing temperature and optionally one or more additional firing temperatures wherein at least one of the firing temperatures is the maximum firing temperature and wherein at least one of the firing temperatures is between about 700°

C. and about 1000°

C., said firing step comprising heating the mixture from 500°

C. to the maximum firing temperature at an average rate of less than or equal to 10°

C./min to produce separate lithium metal oxide phases including LiNi<sub>1−

y</sub>Co_aM³_bM⁴_cO₂ and Li₂M³O₃; and

cooling the LiNi<sub>1−

y</sub>Co_aM³_bM⁴_cO₂ and Li₂M³O₃ compounds.

78. The method according to claim 77, said mixing step comprises mixing source compounds such that M³ includes Ti.

79. The method according to claim 78, wherein said mixing step comprises mixing source compounds such that M⁴ includes Mg.

80. A positive electrode active material, comprising:

at least one electron conducting compound existing in a first single phase having the formula LiM¹<sub>x−

y</sub>{A}_yO_z wherein M¹ is a transition metal, {A} is represented by the formula Σ

w_iB_i wherein B_i comprises at least one element having a Pauling'"'"'s electronegativity not greater than 2.05 and w_i is the fractional amount of element B_i in the total dopant combination such that Σ

w_i=1, 0.95≦

x≦

1.05, 0≦

y≦

x/2, and 1.90≦

z≦

2.10; and

at least one electron insulating and lithium ion conducting lithium metal oxide of the formula LiM²O₃, existing in a second single phase structurally separate from the first single phase of the compound having the formula LiM¹<sub>x−

y</sub>{A}_yO_z wherein M² is at least one tetravalent metal.