Process for the purification of lithium salts

• US 7,981,388 B2
• Filed: 02/23/2007
• Issued: 07/19/2011
• 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 Vladimirovich, Bailey, Wade H. III, Casteel, William Jack Jr.
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US11/710,116
• Publication Number:
  US 20070189946A1
• Time in Patent Office: 1,607 Days
• Field of Search: 423/181, 423/179.5, 423/203, 210/679, 210/681, 232/95.R, 502/415
• US Class Current: 423/179.5
• 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_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.

Claims

1. A method for treating lithium salt wherein the 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;

the method comprising at least one step selected from the group consisting of;

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

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

step c) drying the lithium salt at greater than about 180°

C. under vacuum or nitrogen purge, and

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

recovering treated lithium salts.

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

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

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

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

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

7. The method of claim 1 wherein the alkali or alkaline earth content of the recovered treated lithium salt is less than about 500 ppm.

8. The method of claim 1 wherein the total hydroxyl level of the recovered treated lithium salt is less than about 500 ppm.

9. The method of claim 1 wherein the adsorbent of step a comprises at least one member selected from the group consisting of alumina, titania, silica and carbon.

10. The method of claim 9 wherein the adsorbent comprises alumina.