POSITIVE ELECTRODE MATERIALS FOR LITHIUM ION BATTERIES HAVING A HIGH SPECIFIC DISCHARGE CAPACITY AND PROCESSES FOR THE SYNTHESIS OF THESE MATERIALS

• US 20100086853A1
• Filed: 10/07/2008
• Published: 04/08/2010
• Est. Priority Date: 10/07/2008
• Status: Active Grant

• Current Assignee: Ionblox Incorporated (Zenlabs Energy, Inc.)
• Original Assignee: Envia Systems, Inc.
• Inventors: Venkatachalam, Subramanian, Kumar, Sujeet, Lopez, Herman
• Granted Patent: US 8,389,160 B2
• Time in Patent Office: Days
• US Class Current: 429/223
• CPC Class Codes: C01G 45/1228 of the type [MnO2]n- , e.g. LiMnO2, Li[MxMn1-x]O2
• 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 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/84 one phase coated with the other
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/362 Composites
• 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 4/582 Halogenides
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Positive electrode active materials are described that have a very high specific discharge capacity upon cycling at room temperature and at a moderate discharge rate. Some materials of interest have the formula Li_1+xNi_αMn_βCO_γO₂, where x ranges from about 0.05 to about 0.25, α ranges from about 0.1 to about 0.4, β ranges from about 0.4 to about 0.65, and γ ranges from about 0.05 to about 0.3. The materials can be coated with a metal fluoride to improve the performance of the materials especially upon cycling. Also, the coated materials can exhibit a very significant decrease in the irreversible capacity lose upon the first charge and discharge of the cell. Methods for producing these materials include, for example, a co-precipitation approach involving metal hydroxides and sol-gel approaches.

Claims

1. A positive electrode active material for a lithium ion cell having a discharge capacity at a 10th discharge cycle of at least 240 mAh/g at room temperature at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts.

2. The positive electrode active material of claim 1 having a formula of xLiMO₂.(1−

x)Li₂M′

O₃, where M represents one or more metal ions having an average valance of +3 and M′

represents one or more metal ions having an average valance of +4 and 0<

x<

1.

3. The positive electrode material of claim 2 wherein M′

comprises Mn and M comprises Mn, Co and Ni.

4. The positive electrode material of claim 1 having a formula Li_1+xNi_α

Mn_β

Co_γ

M_δ

O_2-zF_z, where x ranges from about 0.05 to about 0.25, α

ranges from about 0.1 to about 0.4, β

ranges from about 0.4 to about 0.65, γ

ranges from about 0.05 to about 0.3, δ

ranges from about 0 to about 0.1 and z ranges from about 0 to about 0.1, and where M is Mg, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb or combinations thereof.

5. The positive electrode material of claim 1 having a formula Li_1+xNi_α

Mn_β

Co_γ

O₂, where x ranges from about 0.05 to about 0.25, α

ranges from about 0.1 to about 0.4, β

ranges from about 0.4 to about 0.65, and γ

ranges from about 0.05 to about 0.3.

6. The positive electrode material of claim 1 having a formula Li_1.2Ni_0.175CO_0.10Mn_0.525O₂.

7. The positive electrode active material of claim 1 having a discharge capacity at a 10th discharge cycle of at least 245 mAh/g at room temperature at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts.

8. The positive electrode active material of claim 1 having a discharge capacity at a 10th discharge cycle between about 250 and about 275 mAh/g at room temperature at a discharge rate of C/3 when discharged from 4.6 volts to about 2.0 volts.

9. The positive electrode active material of claim 1 comprising a coating of metal fluoride.

10. A secondary lithium ion battery comprising a positive electrode comprising the positive electrode active material of claim 1, a negative electrode comprising a lithium intercalation composition and a separator between the positive electrode and the negative electrode.

11. A positive electrode active material for a lithium ion cell comprising a layered lithium metal oxide comprising +4 metal cations, +3 metal cations and +2 metal cations within a crystalline lattice, wherein the material has a metal/metalloid fluoride coating wherein the positive electrode material has a first cycle irreversible capacity loss at a discharge rate of C/10 of no more than about ⅔

of the first cycle irreversible capacity loss of the uncoated material, and a discharge capacity at the 20th cycle that is at least about 98% of the 5th cycle discharge capacity when discharged at room temperature at a discharge rate of C/3.

12. The positive electrode active material of claim 11 having a formula of xLiMO₂.(1−

x)Li₂M′

O₃, where M represents one or more metal ions having an average valance of +3 and M′

represents one or more metal ions having an average valance of +4, 0<

x<

1.

13. The positive electrode material of claim 11 having a formula Li_1+xNi_α

Mn_β

Co_γ

O₂, where x ranges from about 0.05 to about 0.25, α

ranges from about 0.1 to about 0.4, β

ranges from about 0.4 to about 0.65, and γ

ranges from about 0.05 to about 0.3.

14. The positive electrode active material of claim 11 wherein the material comprises from about 0.5 mole percent to about 4 mole percent metal fluoride.

15. The positive electrode active material of claim 11 wherein the metal fluoride comprises AlF₃.

16. The positive electrode active material of claim 11 wherein the electrode material has a discharge capacity at the 20th cycle that is at least about 98.5% of the 5th cycle discharge capacity when discharged at room temperature with a rate of C/3.

17. The positive electrode active material of claim 11 wherein the electrode active material has a discharge capacity at the 10th cycle from about 250 mAh/g to about 275 mAh/g at room temperature at a discharge rate of C/3 when discharged form 4.6 volts to 2.0 volts.

18. A secondary lithium ion battery comprising a positive electrode comprising the positive electrode active material of claim 11, a negative electrode comprising a lithium intercalation composition and a separator between the positive electrode and the negative electrode.

19. A method for the synthesis of a layered lithium metal oxide composition, the method comprising precipitating a mixed metal hydroxide composition from a solution comprising +2 metal cations wherein the hydroxide composition has a selected composition.

20. The method of claim 19 wherein the solution comprises acetate anions, sulfate anions, nitrate anions or combinations thereof.

21. The method of claim 19 further comprising heating the hydroxide composition to form a corresponding crystalline lithium metal oxide composition.

22. The method of claim 21 wherein the composition has a formula Li_1+xNi_α

Mn_β

Co_γ

O₂, where x ranges from about 0.05 to about 0.25, a ranges from about 0.1 to about 0.4, β

ranges from about 0.4 to about 0.65, and γ

ranges from about 0.05 to about 0.3.

23. The method of claim 19 further comprising the addition of a lithium source in powder form to the metal hydroxide composition to form a mixture and heating the mixture to form a corresponding crystalline lithium metal oxide composition.

24. A method for the synthesis of a layered lithium metal oxide composition, the method comprising calcining at temperatures of at least about 750°

C. a sol gel composition comprising lithium ions and +2 metal cations to form a crystalline layered lithium metal oxide composition.

25. The method of claim 24 wherein the composition has a formula Li_1+xNi_α

Mn_β

Co_γ

O₂, where x ranges from about 0.05 to about 0.25, a ranges from about 0.1 to about 0.4, β

ranges from about 0.4 to about 0.65, and γ

ranges from about 0.05 to about 0.3.

26. The method of claim 24 wherein the sol gel is formed through the addition of a carboxylic acid to a metal acetate solution.