Annealing of mixed metal oxide electrodes to reduce polarization resistance
AssigneeWilson Greatbatch Ltd.
InventorsEsther S. Takeuchi, William C. Thiebolt, III
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Abstract
The thermal treatment of transition metal oxide electrodes such as silver vanadium oxide cathode plates, contacted to titanium current collectors for the purpose of reducing polarization resistance in an alkali metal electrochemical cell, is described. The electrodes are exposed to an elevated temperature of at least about 225° C. for about 8 hours prior to cell fabrication. The present heat treatment regime is particularly useful in cathodes intended for fabrication into a cell powering an implantable medical device with improved polarization resistance as well as reduced heat dissipation.
Claims22
An electrochemical cell comprising anode and cathode electrodes and an activating electrolyte, the improvement comprising;
- the cell having a lithium-containing anode and a cathode, wherein the cathode contains an active material as a reaction product of at least a vanadium oxide salt and a salt of silver, the anode and the cathode exhibiting reduced polarization after having been contacted by the electrolyte, the reduced polarization being the result of the cathode comprising the active material contacted to a conductive current collector and thereafter heat treated at an elevated temperature prior to cell fabrication so that the cell is dischargeable with the cathode exhibiting a resistivity of less than about 0.2 Ωcm.
An electrode, which comprises:
- a) an active material comprising a reaction product of at least a vanadium oxide and a salt of silver;
- and
- b) a conductive current collector contacted with the active material to provide the electrode, wherein the electrode is characterized as having been heat treated at an elevated temperature of at least about 225° C. for at least about 8 hours to provide the electrode having a resistivity of less than about 0.2 Ωcm.
A method for constructing an electrochemical cell comprising the steps of:
- a) providing an anode;
- b) providing a cathode of an active material contacted to a conductive current collector, wherein the active material a reaction product of at least a vanadium salt and a salt of silver;
- c) heating the cathode to a temperature of at least about 225° C. to reduce resistivity of the cathode to less than about 0.2 Ωcm;
- and
- d) activating the anode and cathode with an electrolyte.
A method for constructing an electrochemical cell, comprising the steps of:
- a) providing an anode;
- b) providing a cathode of an active material contacting a conductive current collector, wherein the active material is a reaction product of at least a vanadium salt and a salt of silver;
- c) heating the cathode to a temperature ranging from about 225° C. to about 300° C. to reduce resistivity of the cathode to less than about 0.2 Ωcm;
- and
- d) activating the anode and cathode with an electrolyte.
A method for constructing an electrochemical cell, comprising the steps of:
- a) providing an anode;
- b) providing a cathode of an active material contacting a conductive current collector, wherein the active material is a reaction product of at least a vanadium salt and a salt of silver;
- c) hearing the cathode for about 8 hours to about 16 hours to reduce resistivity of the cathode to less than about 0.2 Ωcm;
- and
- d) activating the anode and cathode with an electrolyte.
A method for constructing an electrochemical cell, comprising the steps of:
- a) providing an anode;
- b) providing a cathode of silver vanadium oxide contacted to a titanium current collector;
- c) heating the cathode to a temperature ranging from about 225° C. to about 250° C. for about 8 hours to about 16 hours to reduce resistivity of the cathode to less than about 0.2 Ωcm;
- and
- d) activating the anode and cathode with an electrolyte.
Dependencies are inferred from the claim text.