Electrolyte additive for lithium rechargeable organic electrolyte battery

Abstract

A large excess of lithium iodide in solution is used as an electrolyte adive to provide overcharge protection for a lithium rechargeable organic electrolyte battery.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENT

In a typical cell configuration such as lithium/lithium hexafluoroarsenate-tetrahydrofuran/titanium disulfide, the organic electrolyte will contain a sufficient amount of lithium iodide additive so that during the overcharging operations all of the lithium iodide is not oxidized to iodine and there is always an excess of lithium iodide present in the solution to combine with the liberated iodine to form stable lithium tri-iodide. The solubility of lithium iodide in tetrahydrofuran solutions is in excess of 1.0 molar and thus enough of lithium iodide can be added to the electrolyte to satisfy the condition that there always be an excess of lithium iodide present to complex with any iodine formed during the overcharging operations. Further, lithium tri-iodide will react with lithium metal to regenerate lithium iodide and restore the cell to its original configuration and be available to provide overcharge protection during the following cycles.

The invention is also applicable to lithium-organic electrolyte primary cells. In fact, the invention is applicable to all ambient temperature lithium-organic electrolyte batteries.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

Claims

1. In a lithium rechargeable organic electrolyte battery including lithium as the anode, a compound selected from the group consisting of titanium disulfide, molybdenum oxide, molybdenum sulfide, vanadium oxide, vanadium sulfide, and chromium oxide as the cathode, and a solution of an organic lithium salt in an organic solvent as the electrolyte, the improvement of using a large excess of lithium iodide in the solution as an electrolyte additive to provide overcharge protection.

2. A lithium rechargeable organic electrolyte battery according to Claim 1 wherein the large excess of lithium iodide in the solutions is about 0.5 to 1.0 molar.

3. A lithium rechargeable organic electrolyte battery according to claim 2 wherein the cathode is titanium disulfide.

4. A lithium rechargeable organic electrolyte battery according to claim 2 wherein the cathode is molybdenum oxide.

5. A lithium rechargeable organic electrolyte battery according to claim 2 wherein the cathode is molybdenum sulfide.

6. A lithium rechargeable organic electrolyte battery according to cClaim 2 wherein the cathode is vanadium oxide.

7. A lithium rechargeable organic electrolyte battery according to claim 2 wherein the cathode is vanadium sulfide.

8. A lithium rechargeable organic electrolyte battery according to claim 2 wherein the cathode is chromium oxide.

9. A lithium rechargeable organic electrolyte battery according to claim 3 wherein the electrolyte is a solution of lithium hexafluoroarsenate in tetrahydrofuran.

10. A lithium rechargeable organic electrolyte battery according to claim 4 wherein the electrolyte is a solution of lithium hexafluoroarsenate in tetrahydrofuran.

11. A lithium rechargeable organic electrolyte battery according to claim 5 wherein the electrolyte is a solution of lithium

12. A lithium rechargeable organic electrolyte battery according to claim 6 wherein the electrolyte is a solution of lithium hexafluoroarsenate in tetrahydrofuran.

13. A lithium rechargeable organic electrolyte battery according to claim 7 wherein the electrolyte is a solution of lithium hexafluoroarsenate in tetrahydrofuran.

14. A lithium rechargeable organic electrolyte battery according to claim 8 wherein the electrolyte is a solution of lithium hexafluoroarsenate in tetrahydrofuran.