Synthesis method for silver vanadium oxide

• US 5,895,733 A
• Filed: 02/03/1997
• Issued: 04/20/1999
• Est. Priority Date: 02/03/1997
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Crespi, Ann M., Chen, Kaimin
• Primary Examiner(s): Nuzzolillo, Maria
• Assistant Examiner(s): CHANEY, CAROL DIANE
• Application Number:
  US08/792,413
• Time in Patent Office: 806 Days
• Field of Search: 429/218, 429/219, 423/592, 423/593
• US Class Current: 429/219
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: C01G 31/00 Compounds of vanadium
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 4/382 Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/48 of inorganic oxides or hydroxides
• CPC Class Codes: H01M 4/483 for non-aqueous cells H01M4/485 takes precedence
• CPC Class Codes: H01M 4/54 of silver
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 50/109 of button or coin shape
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

This present invention provides a method for forming C--SVO without the need for flowing O₂ during its synthesis. A method of forming silver vanadium oxide in accordance with the present invention includes combining AgO with a vanadium-containing compound to form a mixture; and exposing the mixture to a sufficient temperature for a time effective to form silver vanadium oxide.

Claims

1. A method of forming an electrochemical cell, comprising:

combining AgO with a vanadium oxide compound to form a mixture;

exposing the mixture to a sufficient temperature for a time effective to form silver vanadium oxide;

forming a cathode comprising the silver vanadium oxide;

providing an anode;

providing an electrolyte; and

assembling the cathode, the anode, and the electrolyte into the electrochemical cell.

2. The method of claim 1 wherein the silver vanadium oxide has the formula Ag_x V₄ O_y, wherein x is about 1.6 to about 2.2 and y is about 10.5 to about 11.5.

3. The method of claim 2 wherein y is about 11.

4. The method of claim 2 wherein x is about 2.

5. The method of claim 1 wherein the exposing step further comprises simultaneously supplying a gas in a reaction chamber with the AgO and the V₂ O₅, wherein the gas is selected from the group of oxygen, nitrogen, argon, atmospheric air, and mixtures thereof.

6. The method of claim 5 wherein the step of supplying a gas comprises supplying stagnant atmospheric air.

7. The method of claim 1 wherein the step of exposing comprises exposing the mixture to a temperature of about 440 degrees C. to about 550 degrees C. for at about 1 hour to form silver vanadium oxide.

8. The method of claim 7 wherein the step of exposing comprises exposing the mixture to a temperature of about 440 degrees C. to about 550 degrees C. for about 4 hours to about 8 hours to form silver vanadium oxide.

9. A method of making a sealed electrochemical cell for an implantable medical device, the cell comprising a lithium anode in electrical contact with an anode can within which the cell components are housed, a silver vanadium oxide cathode, an electrolyte and a separator disposed between the anode and the cathode, comprising the steps of:

(a) combining divalent silver oxide with a vanadium-containing compound to form a mixture;

(b) exposing the mixture to a sufficient temperature for a time effective to form a silver vanadium oxide material;

(c) combining the silver vanadium oxide material with a binder and a conductivity enhancer to form a cathode material;

(d) forming the cathode from the cathode material; and

(e) placing the cathode, the anode and the separator in the can.

10. The method of claim 9, further comprising the step of sealing the can to form the cell after the anode, the cathode and the separator have been disposed therewithin.

11. The method of claim 9, wherein the electrolyte is introduced in the can after the anode, the cathode and the separator have been disposed therewithin.

12. The method of claim 9, wherein the cathode material combination step includes the step of adding an electrolyte to the cathode material.

13. The method of claim 9, wherein the cathode material combination step includes the step of adding a surfactant to the cathode material.

14. The method of claim 9, wherein the cathode forming step includes the step of pressing the cathode material into a cylindrically-shaped pellet for use in a button cell.

15. The method of claim 9, wherein the cathode forming step includes the step of pressing the cathode material into a strip-shaped configuration for use in a spirally-wound cell.

16. The method of claim 9, wherein the can is formed of a material selected from the group consisting of titanium and stainless steel.

17. The method of claim 9, wherein the electrolyte is selected from the group consisting of a liquid electrolyte, a solid electrolyte, an organic electrolyte and an inorganic electrolyte.

18. The method of claim 9, wherein the binder is material selected from the group consisting of polytetrafluoroethylene, methyl cellulose, ethylene propylene diene terpolymer (EPDM), polyethylene, polypropylene, polyolefins, fluorinated ethylene propylene (FEP), polyvinylidene fluoride, and combinations or mixtures thereof.

19. The method of claim 9, wherein the conductivity enhancer is selected from the group consisting of graphite powder, carbon black, acetylene black powder, and combinations or mixtures thereof.

20. The method of claim 9, wherein the implantable medical device is a defibrillator.