POSITIVE ELECTRODE ACTIVE MATERIAL, METHOD OF MANUFACTURING THE POSITIVE ELECTRODE ACTIVE MATERIAL, AND LITHIUM BATTERY EMPLOYING THE POSITIVE ELECTRODE ACTIVE MATERIAL

• US 20120156565A1
• Filed: 09/23/2011
• Published: 06/21/2012
• Est. Priority Date: 12/20/2010
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kim, Chang-Hyuk, Park, Do-Hyung, Kwon, Seon-Young, Kim, Min-Han, Kim, Ji-Hyun, Lee, Jeong-Seop, Kim, Yoon-Chang
• Granted Patent: US 9,917,305 B2
• Time in Patent Office: Days
• US Class Current: 429/221
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/366 as layered products
• 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 4/525 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

In one aspect, a positive electrode active material is provided, a method of manufacturing the positive electrode active material, and a lithium battery employing the positive electrode active material. The positive electrode active material may have high thermal stability and low capacity deterioration despite repetitive charging and discharging.

Claims

1. A positive electrode active material comprising:

a core comprising a lithium nickel-based complex oxide; and

a complex coating layer formed on a surface of the core and comprising titanium dioxide (TiO₂) and lithium titanium oxide (LiTi_xO_y),

wherein 1≦

x≦

2 and 2.5≦

y≦

3, and

an amount of lithium is higher on the surface of the core than a total average composition of the core.

2. The positive electrode active material of claim 1, wherein the core is formed of at least one compound selected from the group consisting of compounds represented by Formulas 1 through 5 below:

Li_aNi_1-bCo_bO_2-cX_c 

 

[Formula 1]

Li_aNi_1-b-cCo_bM_cA_p 

 

[Formula 2]

Li_aNi_1-b-cCo_bM_cO_2-pX_p 

 

[Formula 3]

Li_aNi_1-b-cMn_bM_cA_p 

 

[Formula 4]

Li_aNi_1-b-eMn_bM_cO_2-pX_p, 

 

[Formula 5]

wherein a, b, c, and p each respectively satisfy 0.95≦

a≦

1.35, 0≦

b≦

0.5, 0≦

c≦

0.5, 0≦

p≦

2, M is at least one element selected from the group consisting of aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), scandium (Sc), yttrium (Y), and a lanthanide element, A is at least one element selected from the group consisting of oxygen (O), fluorine (F), sulfur (S), and phosphorous (P), and X is at least one element selected from the group consisting of F, S, and P.

3. The positive electrode active material of claim 2, wherein 0.95≦

a≦

1.1 in Formulas 1 through 5 in the total average composition of the core, and 1.05≦

a≦

1.35 in Formulas 1 through 5 in a surface composition of the core.

4. The positive electrode active material of claim 1, wherein the complex coating layer has a structure in which LiTi_xO_y crystals are distributed in a TiO₂ matrix.

5. The positive electrode active material of claim 4, wherein, in the complex coating layer, the LiTi_xO_y crystals in the TiO₂ matrix are adjacent to the surface of the core.

6. The positive electrode active material of claim 1, wherein a total amount of TiO₂ and LiTi_xO_y is from about 0.01 to about 50 wt % based on a total weight of the positive electrode active material.

7. The positive electrode active material of claim 1, wherein a total amount of TiO₂ and LiTi_xO_y is from about 0.01 to about 20 wt % based on a total weight of the positive electrode active material.

8. The positive electrode active material of claim 1, wherein a total amount of TiO₂ and LiTi_xO_y is from about 0.01 to about 10 wt % based on a total weight of the positive electrode active material.

14. An electrode for a lithium battery, the electrode comprising the positive electrode active material of claim 1.

15. The electrode for a lithium battery of claim 14, wherein the core is formed of at least one compound selected from the group consisting of compounds represented by Formulas 1 through 5 below:

Li_aNi_1-bCo_bO_2-cX_c 

 

[Formula 1]

Li_aNi_1-b-cCo_bM_cA_p 

 

[Formula 2]

Li_aNi_1-b-cCo_bM_cO_2-pX_p 

 

[Formula 3]

Li_aNi_1-b-cMn_bM_cA_p 

 

[Formula 4]

Li_aNi_1-b-cMn_bM_cO_2-pX_p, 

 

[Formula 5]

wherein a, b, c, and p each respectively satisfy 0.95≦

a≦

1.35, 0≦

b≦

0.5, 0≦

c≦

0.5, 0≦

p≦

2, M is at least one element selected from the group consisting of aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), scandium (Sc), yttrium (Y), and a lanthanide element, A is at least one element selected from the group consisting of oxygen (O), fluorine (F), sulfur (S), and phosphorous (P), and X is at least one element selected from the group consisting of F, S, and P.

16. The electrode for a lithium battery of claim 15, wherein 0.95≦

a≦

1.1 in Formulas 1 through 5 in the total average composition of the core, and 1.05≦

a≦

1.35 in Formulas 1 through 5 in a surface composition of the core.

17. A lithium battery comprising a positive electrode that comprises the positive electrode active material of claim 1.

18. The lithium battery of claim 17, wherein the core is formed of at least one compound selected from the group consisting of compounds represented by Formulas 1 through 5 below:

Li_aNi_1-bCo_bO_2-cX_c 

 

[Formula 1]

Li_aNi_1-b-cCo_bM_cA_p 

 

[Formula 2]

Li_aNi_1-b-cCo_bM_cO_2-pX_p 

 

[Formula 3]

Li_aNi_1-b-cMn_bM_cA_p 

 

[Formula 4]

Li_aNi_1-b-cMn_bM_cO_2-pX_p, 

 

[Formula 5]

wherein a, b, c, and p each respectively satisfy 0.95≦

a≦

1.35, 0≦

b≦

0.5, 0≦

c≦

0.5, 0≦

p≦

2, M is at least one element selected from the group consisting of aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), scandium (Sc), yttrium (Y), and a lanthanide element, A is at least one element selected from the group consisting of oxygen (O), fluorine (F), sulfur (S), and phosphorous (P), and X is at least one element selected from the group consisting of F, S, and P.

19. The electrode for a lithium battery of claim 18, wherein 0.95≦

a≦

1.1 in Formulas 1 through 5 in the total average composition of the core, and 1.05≦

a≦

1.35 in Formulas 1 through 5 in a surface composition of the core.

20. The positive electrode active material of claim 18, wherein a total amount of TiO₂ and LiTi_xO_y is from about 0.01 to about 50 wt % based on a total weight of the positive electrode active material.

9. A method of manufacturing a positive electrode active material, comprising:

mixing a lithium nickel-based complex oxide, in which more lithium exists on a surface than in a total average composition, with a titanium dioxide (TiO₂)-containing solution to prepare a mixture; and

heat-treating the mixture at a temperature from about 300°

C. to about 800°

C. after drying the mixture,

wherein a complex coating layer comprising TiO₂ and lithium titanium oxide (LiTi_xO_y) is formed on the surface of the lithium nickel-based complex oxide, wherein 1≦

x≦

2 and 2.5≦

y≦

3.

10. The method of claim 9, wherein the core is formed of at least one compound selected from the group consisting of compounds represented by Formulas 1 through 5 below:

Li_aNi_1-bCo_bO_2-cX_c 

 

[Formula 1]

Li_aNi_1-b-cCo_bM_cA_p 

 

[Formula 2]

Li_aNi_1-b-cCo_bM_cO_2-pX_p 

 

[Formula 3]

Li_aNi_1-b-cMn_bM_cA_p 

 

[Formula 4]

Li_aNi_1-b-cMn_bM_cO_2-pX_p, 

 

[Formula 5]

wherein a, b, c, and p each respectively satisfy 0.95≦

a≦

1.35, 0≦

b≦

0.5, 0≦

c≦

0.5, 0≦

p≦

2, M is at least one element selected from the group consisting of aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), magnesium (Mg), strontium (Sr), vanadium (V), scandium (Sc), yttrium (Y), and a lanthanide element, A is at least one element selected from the group consisting of oxygen (O), fluorine (F), sulfur (S), and phosphorous (P), and X is at least one element selected from the group consisting of F, S, and P.

11. The method of claim 9, wherein the TiO₂-containing solution is obtained by hydrolyzing an alkoxide, a nitrate, a sulfate, a carbonate, a chloride, or an acetate comprising a Ti metal, or a mixture thereof.

12. The method of claim 9, wherein the mixture further comprises a lithium salt.

13. A method of manufacturing a positive electrode active material, comprising:

preparing a coating solution comprising titanium dioxide (TiO₂) and lithium titanium oxide (LiTi_xO_y), wherein 1≦

x≦

2 and 2.5≦

y≦

3; and

adding a lithium nickel-based complex oxide, in which more lithium exists on a surface than in a total average composition, to the coating solution,

wherein a complex coating layer comprising TiO₂ and LiTi_xO_y is formed on the surface of the lithium nickel-based complex oxide, wherein 1≦

x≦

2 and 2.5≦

y≦

3.