Method for making lithiated metal oxide

• US 6,083,475 A
• Filed: 04/02/1999
• Issued: 07/04/2000
• Est. Priority Date: 04/02/1999
• Status: Expired due to Fees

• Current Assignee: Rentech, Inc.
• Original Assignee: Rentech, Inc.
• Inventors: Chaloner-Gill, Benjamin, Shackle, Dale R.
• Primary Examiner(s): Griffin, Steven P.
• Assistant Examiner(s): Ildebrando, Christina
• Application Number:
  US09/285,552
• Time in Patent Office: 459 Days
• Field of Search: 423/50, 423/64, 423/65, 423/179.5, 423/184, 423/599, 423/593, 429/224, 429/231.2
• US Class Current: 423/594.8
• CPC Class Codes: C01G 31/00 Compounds of vanadium
• CPC Class Codes: C01G 45/1221 Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
• CPC Class Codes: C01P 2006/40 Electric properties
• 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 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention is a simple and reliable method for producing lithiated metal oxides such as those useful as cathode materials in lithium ion electrochemical cells. The method is based on the use of an organic solvent that dissolves both lithium sulfide and elemental sulfur without dissolving the metal oxide or the lithiated product. Lithium sulfide and the metal oxide as a powder are refluxed in the organic solvent under an inert atmosphere. The organic solvent dissolves the lithium sulfide and the dissolved sulfide reduces the metal oxide allowing the intercalation of lithium. At the same time the sulfur that results from the oxidation-reduction reaction is carried away by the solvent thereby promoting the reaction and preventing contamination of the product with sulfur.

Claims

1. A method for converting a metal oxide into a lithiated material for use in an electrochemical cell comprising the steps of:

adding lithium sulfide to an organic solvent in which lithium sulfide and elemental sulfur are soluble but in which the metal oxide is essentially insoluble;

contacting the metal oxide with said lithium sulfide in the organic solvent, whereby the metal oxide is converted into the lithiated material and resulting elemental sulfur is dissolved by the organic solvent; and

removing the lithiated material from the organic solvent.

2. The method of claim 1, wherein the metal oxide is selected from a group consisting of V₂ O₅, LiV₅ O₁₃, MnO₂, V₆ O₁₃, and LiV₃ O₇.9.

3. The method of claim 1, wherein the organic solvent is selected from a group consisting of acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, diethyleneglycol dimethyl ether, diethyleneglycol diethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and poly(ethylene glycol) dimethyl ether.

4. The method of claim 1, wherein the contacting occurs at a temperature between 60°

C. and 100°

C.

5. A method for converting a vanadium oxide or a lithium vanadium oxide into a lithiated material for use in an electrochemical cell comprising the steps of:

adding lithium sulfide to an organic solvent in which lithium sulfide and elemental sulfur are soluble but in which the vanadium oxide or the lithium vanadium oxide is essentially insoluble;

contacting the vanadium oxide or the lithium vanadium oxide with said lithium sulfide in the organic solvent, whereby the vanadium oxide or the lithium vanadium oxide is converted into the lithiated material and resulting elemental sulfur is dissolved by the organic solvent; and

removing the lithiated material from the organic solvent.

6. The method of claim 5, wherein the metal oxide is selected from a group consisting of V₂ O₅, LiV₅ O₁₃, V₆ O₁₃, and LiV₃ O₇.9.

7. The method of claim 5, wherein the organic solvent is selected from a group consisting of acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, diethyleneglycol dimethyl ether, diethyleneglycol diethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and poly(ethylene glycol) dimethyl ether.

8. The method of claim 5, wherein the contacting occurs at a temperature between 60°

C. and 100°

C.

9. A method for converting LiV₃ O₇.9 into lithiated LiV₃ O₇.9 for use in an electrochemical cell comprising the steps of:

adding lithium sulfide to an organic solvent in which lithium sulfide and elemental sulfur are soluble but in which the LiV₃ O₇.9 is essentially insoluble;

contacting the LiV₃ O₇.9 with said lithium sulfide in the organic solvent;

refluxing the organic solvent in an inert gas atmosphere, whereby the LiV₃ O₇.9 is converted into the lithiated LiV₃ O₇.9 and resulting elemental sulfur is dissolved by the organic solvent; and

removing the lithiated LiV₃ O₇.9 from the organic solvent.

10. The method of claim 9, wherein the organic solvent is selected from a group consisting of acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether, diethyleneglycol dimethyl ether, diethyleneglycol diethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and poly(ethylene glycol) dimethyl ether.

11. The method of claim 9, wherein the contacting occurs at a temperature between 60°

C. and 100°

C.