HIGH CAPACITY LITHIUM ION BATTERY FORMATION PROTOCOL AND CORRESPONDING BATTERIES

• US 20130043843A1
• Filed: 08/17/2012
• Published: 02/21/2013
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: Ionblox Incorporated (Zenlabs Energy, Inc.)
• Original Assignee: Envia Systems, Inc.
• Inventors: Li, Bing, Amiruddin, Shabab
• Granted Patent: US 9,159,990 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/056 characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 4/0447 of complete cells or cells stacks
• 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 4/362 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 4/587 for inserting or intercalating light metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Battery formation protocols are used to perform initial charging of batteries with lithium rich high capacity positive electrode to result a more stable battery structure. The formation protocol generally comprises three steps, an initial charge step, a rest period under an open circuit and a subsequent charge step to a selected partial activation voltage. The subsequent or second charge voltage is selected to provide for a desired degree of partial activation of the positive electrode active material to achieve a desired specific capacity while providing for excellent stability with cycling. The formation protocol is particularly effective to stabilize cycling for compositions with moderate lithium enrichment.

Claims

1. A method for the formation of a lithium ion secondary battery comprising a lithium rich metal oxide composition, a negative electrode, a separator between the positive electrode and negative electrode, and an electrolyte comprising lithium ions, the method comprising:

performing a first charge of the battery to a voltage from about 2.1V to about 4.225V;

after completing the first charge, holding the battery at an open circuit for a rest period of at least about 6 hours; and

performing a second charge after the completion of the rest period to a voltage from about 4.275V to about 4.39V.

2. The method of claim 1 wherein the first charge of the battery is to a voltage from about 4.15V to about 4.22V.

3. The method of claim 1 wherein the battery is held at an open circuit rest period from about 8 hours to about 8 days.

4. The method of claim 1 wherein the second charge after the rest period is to a voltage from about 4.28V to about 4.38V.

5. The method of claim 1 wherein the lithium rich metal oxide is approximately represented by x Li₂MnO₃.(1−

x) LiNi_uMn_vCo_wA_yO₂, wherein z=0 and the stoichiometry defines x, u, v, w and y in terms of b, α

, β

, γ and

δ

, and wherein 0.125≦

x≦

0.325.

6. The method of claim 1 wherein the negative electrode comprises graphitic carbon.

7. The method of claim 1 wherein after charging the battery to 4.35V and storing the battery at an open circuit voltage for one week, the negative electrode of the battery comprises no more than about 125 ppm of the combination of Mn, Co and Ni.

8. The method of claim 1 wherein after cycling for 2500 cycles between 4.24V to 2.73V at a 1 C Charge and 2 C discharge, the battery maintains at least 92% of capacity.

9. The method of claim 1 wherein the electrolyte comprises LiPF₆ and/or LiBF₄ at a total concentration from about 0.9M to about 2.5M and a solvent comprising ethylene carbonate and an organic solvent comprising dimethyl carbonate, methyl ethyl carbonate, γ

-butyrolactone, γ

-valerolactone or a combination thereof.

10. The method of claim 9 wherein the electrolyte further comprises a lithium salt additive.

11. A lithium ion battery comprising a positive electrode comprising an active material, a negative electrode, a separator between the positive electrode and negative electrode, and an electrolyte comprising lithium ions, wherein the positive electrode active material comprises a lithium rich metal oxide that can be approximately represented by the formula Li_1+bNi_α

Mn_β

Co_γ

A_δ

O<sub>2−

z</sub>F_z, where b ranges from about 0.01 to about 0.3, α

ranges from 0 to about 0.4, β

range from about 0.2 to about 0.65, γ

ranges from about 0 to about 0.46, δ

ranges from about 0.001 to about 0.15, and z ranges from 0 to about 0.2 with the proviso that both α and

γ

are not zero, and where A is a metal different from Ni, Mn and Co or a combination thereof, and wherein after charging the battery to 4.35V at a rate of C/10, storing the charged battery with an open circuit for a week at room temperature and fully discharging the battery, the negative electrode comprises no more than about 150 ppm by weight manganese.

12. The lithium ion battery of claim 11 wherein after charging to 4.35V and storing the battery in an open circuit voltage for 1 week, the negative electrode comprises no more than about 135 ppm by weight manganese.

13. The lithium ion battery of claim 11 wherein after charging to 4.35V and storing the battery at an open circuit voltage for a week, the negative electrode comprises no more than about 200 ppm of the combination of Mn, Co and Ni.

14. A lithium ion battery comprising:

a positive electrode comprising a positive electrode active material that comprises a lithium rich metal oxide;

a negative electrode comprising a lithium intercalation/alloying composition;

a non-aqueous electrolyte comprising lithium ions;

a separator between the negative electrode and the positive electrode; and

wherein the battery has been cycled through a formation cycle and wherein at the 200th cycle, the battery has a specific discharge capacity based on the mass of the positive electrode active composition of at least about 140 mAh/g at a discharge rate of 1 C from 4.35V to 2.0V that is at least about 97% of the 5th cycle specific discharge capacity.

15. The lithium ion battery of claim 14 wherein the lithium rich metal oxide is approximately represented by x Li₂MnO₃.(1−

x) LiNi_uMn_vCo_wA_yO₂, wherein z=0 and the stoichiometry defines x, u, v, w and y in terms of b, α

, β

, γ and

δ

.

16. The lithium ion battery of claim 15 wherein 0.125≦

x≦

0.325.

17. The lithium ion battery of claim 14 wherein the negative electrode comprises graphitic carbon.

18. The lithium ion battery of claim 14 wherein the electrolyte comprises LiPF₆ and/or LiBF₄ at a total concentration from about 0.9M to about 2.5M and a solvent comprising ethylene carbonate and an organic solvent comprising dimethyl carbonate, methyl ethyl carbonate, γ

-butyrolactone, γ

-valerolactone or a combination thereof.

19. The lithium ion battery of claim 14 wherein the positive electrode active material has a discharge specific capacity at a rate of 2 C from 4.35V to 2.5V at the 10th discharge cycle that is at least about 140 mAh/g and that is at least 87.5% of the discharge specific capacity at a rate of C/5 from 4.35V to 2.5V at the 11th discharge cycle.

20. The lithium ion battery of claim 14 wherein the positive electrode active material has a discharge specific capacity at a rate of C/3 from 4.35V to 2.5V at the 5th discharge cycle that is at least about 160 mAh/g and having a calendar life at 85% state of charge at 30 degrees C. of at least about 2 years based on discharge capacity decay of no more than about 20%.

21. The lithium ion battery of claim 14 wherein the positive electrode active material has a stabilization coating over the lithium rich metal oxide.

22. The lithium ion battery of claim 14 having a discharge energy density of at least about 150 Wh/kg at a discharge rate of C/3 from 4.35V to 2V.

23. A lithium ion battery comprising a positive electrode comprising an active material, a negative electrode, a separator between the positive electrode and negative electrode, and an electrolyte comprising lithium ions, wherein the positive electrode active material comprises a lithium rich metal oxide that can be approximately represented by the formula Li_1+bNi_α

Mn_β

Co_γ

A_δ

O<sub>2−

z</sub>F_z, where b ranges from about 0.01 to about 0.3, α

ranges from 0 to about 0.4, β

range from about 0.2 to about 0.65, γ

ranges from about 0 to about 0.46, δ

ranges from about 0.001 to about 0.15, and z ranges from 0 to about 0.2 with the proviso that both α and

γ

are not zero, and where A is a metal different from Ni, Mn and Co or a combination thereof, and wherein the positive electrode active material has a discharge specific capacity at a rate of 2 C from 4.35V to 2.5V at the 10th discharge cycle that is at least about 140 mAh/g and that is at least 87.5% of the discharge specific capacity at a rate of C/5 from 4.35V to 2.5V at the 11th discharge cycle.

24. The lithium ion battery of claim 23 wherein the positive electrode active material has a discharge specific capacity at a rate of 2 C from 4.35V to 2.5V at the 10th discharge cycle that is at least 89% to about 92.5% of the discharge specific capacity at a rate of C/5 from 4.35V to 2.5V at the 11th discharge cycle.

25. The lithium ion battery of claim 23 wherein the lithium rich metal oxide is approximately represented by x Li₂MnO₃.(1−

x) LiNi_uMn_vCo_wA_yO₂, wherein z=0 and the stoichiometry defines x, u, v, w and y in terms of b, α

, β

, γ and

δ

, and wherein 0.125≦

x≦

0.325.

26. The lithium ion battery of claim 23 wherein the negative electrode comprises graphitic carbon.

27. A lithium ion battery comprising a positive electrode comprising a positive electrode active material that comprises a lithium rich metal oxide, a negative electrode, a separator between the positive electrode and negative electrode, and an electrolyte comprising lithium ions, wherein the lithium rich metal oxide can be approximately represented by the formula Li_1+bNi_α

Mn_β

Co_γ

A_δ

O<sub>2−

z</sub>F_z, where b ranges from about 0.01 to about 0.3, α

ranges from 0 to about 0.4, β

range from about 0.2 to about 0.65, γ

ranges from about 0 to about 0.46, δ

ranges from about 0.001 to about 0.15, and z ranges from 0 to about 0.2 with the proviso that both α and

γ

are not zero, and where A is a metal different from Ni, Mn and Co or a combination thereof, and wherein the positive electrode active material has a discharge specific capacity at a rate of C/3 from 4.35V to 2.5V at the 5th discharge cycle that is at least about 160 mAh/g and having a calendar life at an 85% state of charge at 30 degrees C. of at least about 2 years based on discharge capacity decay of no more than about 20%.

28. The lithium ion battery of claim 27 wherein the positive electrode material has a calendar life at 30 degree C. of at least about 3 years based on discharge capacity decay of no more than about 20%.

29. The lithium ion battery of claim 27 wherein the lithium rich metal oxide is approximately represented by x Li₂MnO₃.(1−

x) LiNi_uMn_yCo_wA_yO₂, wherein z=0 and the stoichiometry defines x, u, v, w and y in terms of b, α

, β

, γ and

δ

, and wherein 0.125≦

x≦

0.325.

30. The lithium ion battery of claim 27 wherein the negative electrode comprises graphitic carbon.