LITHIUM TRANSITION METAL-BASED COMPOUND POWDER FOR POSITIVE ELECTRODE MATERIAL IN LITHIUM RECHARGEABLE BATTERY, METHOD FOR MANUFACTURING THE POWDER, SPRAY DRIED PRODUCT OF THE POWDER, FIRING PRECURSOR OF THE POWDER, AND POSITIVE ELECTRODE FOR LITHIUM RECHARGEABLE BATTERY AND LITHIUM RECHARGEABLE BATTERY USING THE POWDER

• US 20090104530A1
• Filed: 04/06/2007
• Published: 04/23/2009
• Est. Priority Date: 04/07/2006
• Status: Active Grant

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Terada, Kaoru, Shizuka, Kenji, Okahara, Kenji, Imura, Hiroyuki
• Granted Patent: US 8,535,829 B2
• Time in Patent Office: Days
• US Class Current: 429/223
• 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 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 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/14 Pore volume
• CPC Class Codes: C01P 2006/16 Pore diameter
• CPC Class Codes: C01P 2006/17 Pore diameter distribution
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

There is provided a powder of a lithium transition-metal compound for a positive-electrode material in a lithium secondary battery, in which the use of the powder as that of a positive-electrode material in a lithium secondary battery achieves a good balance among improvement in battery performance, cost reduction, resistance to a higher voltage, and a higher level of safety. The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery is characterized in that in a mercury intrusion curve obtained by mercury intrusion porosimetry, the amount of mercury intruded is in the range of 0.8 cm³/g to 3 cm³/g when the pressure is increased from 3.86 kPa to 413 MPa.

Claims

1. :

A powder of a lithium transition-metal compound for a positive-electrode material in a lithium secondary battery, wherein in a mercury intrusion curve obtained by mercury intrusion porosimetry, the amount of mercury intruded is in the range of 0.8 cm³/g to 3 cm³/g when the pressure is increased from 3.86 kPa to 413 MPa.

2. :

The powder of the lithium transition-metal compound according to claim 1, wherein a pore-size distribution curve obtained by mercury intrusion porosimetry has a main peak with a peak top that is present at a pore radius of 300 nm to 1,000 nm and does not have a sub-peak with a peak top that is present at a pore radius greater than or equal to 80 nm and less than 300 nm.

3. :

The powder of the lithium transition-metal compound according to claim 1, wherein in a pore-size distribution curve obtained by mercury intrusion porosimetry, a main peak with a peak top that is present at a pore radius of 300 nm to 1,000 μ

m has a pore volume of 0.5 cm³/g to 1.5 cm³/g.

4. :

The powder of the lithium transition-metal compound according to claim 1, wherein the median diameter is in the range of 0.6 μ

m to 5 μ

m and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

5. :

The powder of the lithium transition-metal compound according to claim 1, wherein the powder is composed of a lithium-nickel-manganese-cobalt composite oxide of the composition formula (I)

Li[Li_z/(2+z){(Li_xNi<sub>(1−

3x)/2</sub>Mn_(1+x)/2)<sub>1−

y</sub>Co_y}_2/(2+z)]O₂ 

 

composition formula (I)

wherein 0≦

x≦

0.33, 0≦

y≦

0.2, and −

0.02≦

z≦

0.2(1−

y)(1−

3x).

6. :

The powder of the lithium transition-metal compound according to claim 1, wherein the bulk density is in the range of 0.5 to 1.5 g/cm³.

7. :

The powder of the lithium transition-metal compound according to claim 1, wherein the BET specific surface area is in the range of 1.5 to 5 m²/g.

8. :

The powder of the lithium transition-metal compound according to claim 1, wherein the carbon content C (% by weight) is in the range of 0.005% by weight to 0.2% by weight.

9. :

A method for producing the powder of the lithium transition-metal compound according to claim 1, the method comprising pulverizing a lithium compound and at least one transition-metal compound in a liquid medium to form a slurry, spray-drying the slurry containing these compounds uniformly dispersed to form a spray-dried product, and firing the spray-dried product in an oxygen-containing gas atmosphere.

10. :

The method according to claim 9, wherein the spray-dried product is mixed with at least one compound that forms pores in secondary particles of the spray-dried product to form a firing precursor.

11. :

The method according to claim 10, wherein the at least one compound that forms the pores is a compound that generates one or more decomposition gases or sublimes during firing to form pores in the secondary particles.

12. :

The method according to claim 11, wherein one of the decomposition gases is carbon dioxide gas (CO₂).

13. :

The method according to claim 9, wherein the lithium compound is lithium carbonate.

17. :

A positive electrode for a lithium secondary battery, comprising a positive-electrode active-material layer on a current collector, the layer including the powder of the lithium transition-metal compound according to claim 1 and a binder.

18. :

A lithium secondary battery comprising a negative electrode capable of intercalating and deintercalating lithium, a nonaqueous electrolyte containing a lithium salt, and a positive electrode capable of intercalating and deintercalating lithium, wherein the positive electrode is the positive electrode for a lithium secondary battery according to claim 17.

14. :

A spray-dried product comprising a lithium transition-metal compound, the spray-dried product being prepared by pulverizing a lithium compound and at least one transition-metal compound in a liquid medium to form a slurry and spray-drying the slurry containing these compounds uniformly dispersed, wherein the median diameter of the spray-dried product is in the range of 0.01 μ

m to 4 μ

m and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

15. :

The spray-dried product according to claim 14, wherein the BET specific surface area is in the range of 10 to 70 m²/g.

16. :

A firing precursor comprising the spray-dried product according to claim 14 and at least one compound that forms pores in secondary particles.

19. :

A powder of a lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery, the composite oxide being represented by the composition formula (I′

);

Li[Li<sub>z′

/(2+z′

)</sub>{(Ni<sub>(1+y′

)/2</sub>Mn<sub>(1−

y′

)/2</sub>)<sub>1−

x′</sub>

Co_x′

}<sub>2/(2+z′

)</sub>]O₂ 

 

(I′

)

where 0≦

x′

≦

0.1, −

0.1≦

y′

≦

0.1, and (1−

x′

)(0.05−

0.98y′

)≦

z′

≦

(1−

x′

) 0.15−

0.88y′

), wherein the composite oxide has a crystal structure assigned to a layered structure, and wherein in powder X-ray diffraction measurement using CuKα

radiation, 0.01≦

FWHM (110)≦

0.2, where FWHM (110) represents the half-width of the (110) diffraction peak observed at a diffraction angle 2θ

of about 64.5°

.

20. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein in the composition formula (I′

), 0.04≦

x′

≦

0.099, −

0.03≦

y′

≦

0.03, and (1−

x′

)(0.08−

0.98y′

)≦

z′

≦

(1−

x′

)(0.13−

0.88y′

).

21. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein in powder X-ray diffraction measurement using CuKα

radiation, no diffraction peak from a heterophase is observed on the higher-angle side of the peak top of each of the (018) diffraction peak at a diffraction angle 2θ

of about 64°

, the (110) diffraction peak at a diffraction angle 2θ

of about 64.5°

, and the (113) diffraction peak at a diffraction angle 2θ

of about 68°

, or in the case where a diffraction peak from a heterophase is observed, the ratio of the integrated intensity of the diffraction peak from the heterophase to the integrated intensity of a corresponding one of the diffraction peaks from a target crystal phase is within ranges described below;

0≦

I_018*/I₀₁₈≦

0.20,

0≦

I_110*/I₁₁₀≦

0.25, and

0≦

I_113*/I₁₁₃≦

0.30,

where I₀₁₈ represents the integrated intensity of the (018) diffraction peak, I110 represents the integrated intensity of the (110) diffraction peak, I113 represents the integrated intensity of the (113) diffraction peak, I_018* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (018) diffraction peak, I_110* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (110) diffraction peak, and I_113* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (113) diffraction peak.

22. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein in a mercury intrusion curve obtained by mercury intrusion porosimetry, the amount of mercury intruded is in the range of 0.7 cm³/g to 1.5 cm³/g when the pressure is increased from 3.86 kPa to 413 MPa.

23. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein a pore-size distribution curve obtained by mercury intrusion porosimetry has a main peak with a peak top that is present at a pore radius of 300 nm to 1,000 nm and does not have a sub-peak with a peak top that is present at a pore radius greater than or equal to 80 nm and less than 300 nm.

24. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein in a pore-size distribution curve obtained by mercury intrusion porosimetry, a main peak with a peak top that is present at a pore radius of 300 μ

m to 1,000 μ

m has a pore volume of 0.3 cm³/g to 1.0 cm³/g.

25. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein the median diameter is in the range of 1 μ

m to 5 μ

m, and wherein the median diameter is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

26. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein the bulk density is in the range of 0.5 to 1.7 g/cm³.

27. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein the BET specific surface area is in the range of 1.4 to 3 m²/g.

28. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein the carbon content C (% by weight) is in the range of 0.005% by weight to 0.05% by weight.

29. :

The powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, wherein the volume resistivity of the powder that is compacted at a pressure of 40 MPa is in the range of 1×

10³ Ω

·

cm to 1×

10⁶ Ω

·

cm.

30. :

A method for producing the powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19, the method comprising a slurry preparation step of pulverizing a lithium compound, a nickel compound, a manganese compound, and a cobalt compound in a liquid medium to form a slurry containing these compounds uniformly dispersed, a spray-drying step of spray-drying the resulting slurry to form a spray-dried product, and a firing step of firing the spray-dried product in an oxygen-containing gas atmosphere at a temperature T (°

C.) of 940°

C.≦

T≦

1,200°

C.

31. :

The method according to claim 30 for producing the powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery, wherein the lithium compound is lithium carbonate.

32. :

The method according to claim 30 for producing the powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery, wherein in the slurry preparation step, the lithium compound, the nickel compound, the manganese compound, and the cobalt compound are pulverized in the liquid medium in such a manner that the median diameter is in the range of 0.3 μ

m or less and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz), and wherein in the spray-drying step, spray drying is performed under the conditions of 50 cp≦

V≦

4,000 cp and 1,500≦

G/S≦

5,000, where V represents the viscosity (cp) of the slurry during the spray drying, (L/min) represents the amount of slurry fed, and G represents the amount of gas fed (L/min).

35. :

A positive electrode for a lithium secondary battery, comprising a positive-electrode active-material layer on a current collector, the layer including the powder of the lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery according to claim 19 and a binder.

36. :

A lithium secondary battery comprising a negative electrode capable of intercalating and deintercalating lithium, a nonaqueous electrolyte containing a lithium salt, and a positive electrode capable of intercalating and deintercalating lithium, wherein the positive electrode is the positive electrode for a lithium secondary battery according to claim 35.

37. :

The lithium secondary battery according to claim 36, wherein the battery is designed in such a manner that the charging potential of the positive electrode is 4.35 V or more (vs. Li/Li+) in a fully charged state.

33. :

A spray-dried powder of a lithium-nickel-manganese-cobalt composite oxide prepared by pulverizing a lithium compound, a nickel compound, a manganese compound, and a cobalt compound in a liquid medium to form a slurry containing these compounds uniformly dispersed and spray-drying the resulting slurry, and the spray-dried powder serving as a precursor for a powder of a lithium-nickel-manganese-cobalt composite oxide for a positive-electrode material in a lithium secondary battery, wherein the median diameter of the spray-dried powder is in the range of 0.01 μ

m to 4 μ

m and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

34. :

The spray-dried powder according to claim 33, wherein the BET specific surface area is in the range of 10 to 100 m²/g.

38. :

A powder of a lithium transition-metal compound for a positive-electrode material in a lithium secondary battery, comprising a lithium transition-metal compound, as a main component, capable of intercalating and deintercalating lithium ions, wherein the powder is prepared by incorporating at least one additive that inhibits grain growth and sintering during firing in the main component in an amount greater than or equal to 0.01 mol % and less than 2 mol % with respect to the total molar amount of the transition-metal elements in the main component and then performing firing.

39. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the additive is an oxide that contains at least one element (hereinafter, referred to as an “

additive element”

) selected from Mo, W, Nb, Ta, and Re.

40. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the atomic ratio of the total amount of the additive element to the total amount of metal elements except Li and the additive element on surfaces of primary particles is five or more times the atomic ratio of the total amount of the additive element to the total amount of the metal elements except Li and the additive element in the entire particles.

41. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the median diameter is in the range from 0.1 μ

m to 3 μ

m and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

42. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the primary particles have an average diameter of 0.1 μ

m to 0.9 μ

m.

43. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the BET specific surface area is in the range of 1.5 m²/g to 5 m²/g.

44. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein in a mercury intrusion curve obtained by mercury intrusion porosimetry, the amount of mercury intruded is in the range of 0.7 cm³/g to 1.5 cm³/g when the pressure is increased from 3.86 kPa to 413 MPa.

45. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein a pore-size distribution curve obtained by mercury intrusion porosimetry has at least one main peak with a peak top that is present at a pore radius of 300 nm to 1,000 nm and does not have a sub-peak with a peak top that is present at a pore radius greater than or equal to 80 μ

m and less than 300 nm.

46. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein in a pore-size distribution curve obtained by mercury intrusion porosimetry, a peak with a peak top that is present at a pore radius of 300 μ

m to 1,000 μ

m has a pore volume of 0.4 cm³/g to 1 cm³/g.

47. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the bulk density is in the range of 0.5 g/cm³ to 1.7 g/cm³.

48. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the volume resistivity of the powder that is compacted at a pressure of 40 MPa is in the range of 1×

10³Ω

·

cm to 1×

10⁶ ·

cm.

49. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, wherein the powder mainly comprises a lithium-nickel-manganese-cobalt composite oxide having a crystal structure assigned to a layered structure.

50. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 49, wherein the compound is represented by the composition formula (I″

);

LiMO₂ 

 

(I″

)

where M represents Li, Ni, and Mn, or M represents Li, Ni, Mn, and Co, the Mn/Ni molar ratio is in the range of 0.8 to 5, the Co/(Mn+Ni+Co) molar ratio is in the range of 0 to 0.30, and the ratio of Li to M is in the range of 0.001 to 0.2.

51. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 49, wherein the powder is prepared by firing at 970°

C. or higher in an oxygen-containing gas atmosphere.

52. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 49, wherein the carbon content C (% by weight) is in the range of 0.005% by weight to 0.05% by weight.

53. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 50, wherein M in the composition formula (I″

) is represented by the formula (II′

);

M=Li<sub>z″

/(2+z″

)</sub>{(Ni<sub>(1+y′

)/2</sub>Mn<sub>(1−

y″

)/2</sub>)<sub>1−

x″</sub>

Co_x″

}<sub>2/(2+z″

)</sub> 

 

(II″

)

where 0≦

x″

≦

0.1, −

0.1≦

y″

≦

0.1, and (1−

x″

)(0.05−

0.98y″

)≦

z″

≦

(1−

x″

) (0.20−

0.88y″

).

54. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 53, wherein in powder X-ray diffraction measurement using CuKα

radiation, 0.01≦

FWHM (110)≦

0.2, where FWHM (110) represents the half-width of the (110) diffraction peak observed at a diffraction angle 2θ

of about 64.5°

.

55. :

The powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 53, wherein in powder X-ray diffraction measurement using CuKα

radiation, no diffraction peak from a heterophase is observed on the higher-angle side of the peak top of each of the (018) diffraction peak at a diffraction angle 2θ

of about 64°

, the (110) diffraction peak at a diffraction angle 2θ

of about 64.5°

, and the (113) diffraction peak at a diffraction angle 2θ

of about 68°

, or in the case where a diffraction peak from a heterophase is observed, the ratio of the integrated intensity of the diffraction peak from the heterophase to the integrated intensity of a corresponding one of the diffraction peaks from a target crystal phase is within ranges described below;

0≦

I_018*/I₀₁₈≦

0.20,

0≦

I_110*/I₁₁₀≦

0.25, and

0≦

I_113*/I₁₁₃≦

0.30,

where I₀₁₈ represents the integrated intensity of the (018) diffraction peak, I₁₁₀ represents the integrated intensity of the (110) diffraction peak, I₁₁₃ represents the integrated intensity of the (113) diffraction peak, I_018* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (018) diffraction peak, I_110* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (110) diffraction peak, and I_113* represents the integrated intensity of the diffraction peak from the heterophase observed on the higher-angle side of the peak top of the (113) diffraction peak.

56. :

A method for producing the powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38, the method comprising a slurry preparation step of pulverizing a lithium compound, a compound of at least one transition metal selected from V, Cr, Mn, Fe, Co, Ni, and Cu, and an additive that inhibits grain growth and sintering during firing in an liquid medium to form a slurry containing these compounds uniformly dispersed, a spray-drying step of spray-drying the resulting slurry to form a spray-dried powder, and a firing step of firing the spray-dried powder.

57. :

The method for producing the powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 56, wherein in the slurry preparation step, the lithium compound, the transition-metal compound, and the additive are pulverized in the liquid medium in such a manner that the median diameter is in the range of 0.4 μ

m or less and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz), and wherein in the spray-drying step, spray drying is performed under the conditions of 50 cp≦

V≦

4,000 cp and 1,500≦

G/S≦

5,000, where V represents the viscosity (cp) of the slurry during the spray drying, S represents the amount of slurry fed (L/min), and G represents the amount of gas fed (L/min).

58. :

The method for producing the powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 56, wherein the spray-dried powder contains at least a nickel compound, a manganese compound, and a cobalt compound as the transition-metal compound and is fired at a temperature of 970°

C. or higher in an oxygen-containing gas atmosphere in the firing step.

59. :

The method for producing the powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 56, wherein the lithium compound is lithium carbonate.

62. :

A positive electrode for a lithium secondary battery, comprising a positive-electrode active-material layer on a current collector, the layer including the powder of the lithium transition-metal compound for a positive-electrode material in a lithium secondary battery according to claim 38 and a binder.

63. :

A lithium secondary battery comprising a negative electrode capable of intercalating and deintercalating lithium, a nonaqueous electrolyte containing a lithium salt, and a positive electrode capable of intercalating and deintercalating lithium, wherein the positive electrode is the positive electrode for a lithium secondary battery according to claim 62.

60. :

A spray-dried product prepared by pulverizing a lithium compound, a compound of at least one transition metal selected from V, Cr, Mn, Fe, Co, Ni, and Cu, and an additive that inhibits grain growth and sintering during firing in an liquid medium to form a slurry containing these compounds uniformly dispersed and spray-drying the resulting slurry, and the spray-dried product serving as a precursor for a powder of a lithium transition-metal compound for a positive-electrode material in a lithium secondary battery, wherein the median diameter of the spray-dried product is in the range of 0.01 μ

m to 4 μ

m and is determined from volume-based particle diameters measured with a laser diffraction/scattering particle size distribution analyzer using the refractive index set at 1.24, and the measurement is made after a five-minute ultrasonic dispersion (power;

30 W, frequency;

22.5 kHz).

61. :

The spray-dried product according to claim 60, wherein the BET specific surface area is in the range of 10 m²/g to 100 m²/g.