High purity lithium polyhalogenated boron cluster salts useful in lithium batteries

• US 20070189946A1
• Filed: 02/23/2007
• Published: 08/16/2007
• Est. Priority Date: 08/23/2004
• Status: Active Grant

• Current Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Ivanov, Sergei, Casteel, William, Bailey, Wade
• Granted Patent: US 7,981,388 B2
• Time in Patent Office: Days
• US Class Current: 423/179.500
• CPC Class Codes: C01B 35/06 Boron halogen compounds
• CPC Class Codes: C01B 35/068 Halogenated hydrides
• CPC Class Codes: C01D 13/00 Compounds of sodium or potassium not provided for elsewhere
• CPC Class Codes: C01D 15/00 Lithium compounds
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention relates to lithium secondary batteries comprising a negative electrode, a positive electrode, a separator and a lithium-based electrolyte carried in an aprotic solvent, and to the electrolyte compositions, and to methods for purifying battery active materials. The electrolyte comprises at least one solvent and a lithium salt of the formula:
Li₂B₁₂F_xH_12-x-yZ_ywhere x+y is from 3 to 12, and x and y are independently from 0 to 12, and Z comprises at least one of Cl and Br.

Claims

1. A method for treating lithium salts comprising at least one step selected from the group of:

a) dissolving the salt in an aprotic organic solvent to form a solution and passing said solution through an alumina column,

b) dissolving the salt in a solvent to form a solution, and passing said solution through a cation exchange column in Li⁺ form,

c) drying the salt at greater than about 180°

C. under vacuum or nitrogen purge,

d) dissolving the salt in an aprotic organic solvent to form a solution and passing said solution through a Li-substituted molecular sieve, and;

recovering lithium salts.

2. The method of claim 1 wherein the step comprises:

dissolving the salt in a solvent to form a solution, and passing said solution through a cation exchange column in Li⁺ form.

3. The method of claim 1 wherein the step comprises:

drying the salt at a temperature greater than about 180°

C. under dynamic vacuum or dynamic nitrogen purge.

4. The method of claim 1 wherein the step comprises:

dissolving the salt in at least one aprotic organic solvent to form a solution and passing said solution through a Li-substituted molecular sieve.

5. The method of claim 1 wherein the step comprises:

dissolving the salt in an aprotic organic solvent to form a solution and passing said solution through an alumina column.

6. The method of claim 1 wherein the recovered salt is substantially free of water, HF and non-lithium metal cations.

7. The method of claim 1 wherein the step comprises drying the salt at a temperature greater than about 180°

C. under nitrogen purge.

8. The method of claim 1 wherein the alkali or alkaline earth content of said salt is less than about 500 ppm.

9. The method of claim 1 wherein the total hydroxyl containing impurity level is of said salt is less than about 500 ppm.

10. The method of claim 1 wherein said lithium salt comprises:

Li₂B₁₂F_xH_12-x-yZ_y

where x+y is from 3 to 12, and x and y are independently from 0 to 12, and Z comprises at least one of Cl and Br.

11. The method of claim 1 wherein the salt is substantially free of water, HF and non-lithium metal cations.

12. A method for removing impurities from a material comprising at least one member selected from the group consisting of salts, battery electrolytes and components and precursors thereof by at least one of the following methods:

a) dissolving the material in at least one organic solvent to form a solution and passing said solution through an adsorbent,

b) dissolving the material in at least one solvent to form a solution, and passing said solution through a cation exchange medium,

c) drying the material at a temperature and under conditions sufficient to volatize the impurity,

d) dissolving the material in at least one aprotic organic solvent to form a solution and passing said solution through a sieve.

13. The method of claim 12 wherein said material comprises a lithium battery electrolyte comprising at least one lithium containing compound and at least one solvent selected from the group consisting of organic carbonates, esters, ketones, and nitrites

14. The method of claim 12 wherein the material comprises B₁₂F_xH_12-x-yZ_y (2-) anion wherein x is greater than 8 and less than or equal to 12.

15. The method of claim 12 wherein the adsorbent comprises at least one member selected from the group consisting of alumina, titania, silica and carbon.

16. The method of claim 15 wherein the adsorbent comprises alumina.

17. The method of claim 12 wherien the material comprises K₂B₁₂F_xZ_12-x