Lithium rechargeable inorganic electrolyte cell

• US 6,511,773 B1
• Filed: 06/30/2000
• Issued: 01/28/2003
• Est. Priority Date: 06/30/2000
• Status: Expired due to Fees

• Current Assignee: Lithium Energy Associates, Inc.
• Original Assignee: Lithium Energy Associates, Inc.
• Inventors: Dampier, Frederick W.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): WILLS, MONIQUE M
• Application Number:
  US09/608,547
• Time in Patent Office: 942 Days
• Field of Search: 429/231.95, 429/220, 429/188, 429/346, 320/124, 320/127, 320/130, 320/131
• US Class Current: 429/231.95
• CPC Class Codes: H01M 10/0563 Liquid materials, e.g. for Li-SOCl2 cells
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/446 Initial charging measures
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/043 involving compressing or compaction
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/40 Alloys based on alkali metals
• CPC Class Codes: H01M 4/582 Halogenides
• CPC Class Codes: H01M 50/426 Fluorocarbon polymers
• CPC Class Codes: H01M 50/437 Glass
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A rechargeable cell with an alkali or alkaline earth metal electrode with a coulombic capacity about the same as a metal halide electrode such as CuCl₂, CuBr₂, and the like, or a metal oxide positive electrode such as LiCoO₂, MnO₂ and the like or a carbonaceous positive electrode and a sulfur dioxide electrolyte solvent containing a salt that produces a halogen and/or a Lewis acid on overcharge is disclosed. On most discharges, the active metal of the negative electrode is anodically dissolved and any dendrites are anodically dissolved or electrically isolated and scavenged. About every 4 to 50 cycles, the cell is overdischarged in reversal to reduce the state of charge of the positive electrode relative to the negative electrode and compensate for undercharging of the negative electrode during recycling.

Claims

1. A rechargeable non-aqueous electrochemical cell comprising;

an alkali or alkaline earth metal negative electrode;

a metal halide, carbon or metal oxide positive electrode, said positive electrode material being admixed with at least 2 wt % of a carbonaceous conductive material;

a porous separator; and

an SO₂ electrolyte solvent comprising a dissolved electrolyte salt capable of being oxidized to produce a halogen and/or a Lewis acid on overcharge or overdischarge with voltage reversal, wherein said negative electrode has an initial discharge capacity of not greater than 150% of the rechargeable coulombic capacity of the positive electrode and wherein all alkali or alkaline earth metal in said negative electrode can be anodically dissolved during discharge.

2. The electrochemical cell of claim 1 wherein said positive electrode is CuCl₂ or CuBr₂.

3. The electrochemical cell of claim 1 wherein said negative electrode comprises metallic lithium.

4. The electrochemical cell of claim 1 wherein said electrolyte salt is an aluminum halide salt.

5. The electrochemical cell of claim 1 wherein said electrolyte salt is a gallium halide salt.

6. The electrochemical cell of claim 1 wherein said negative electrode is lithium, said positive electrode is CuCl₂ admixed with at least 5 wt % carbon material and said electrolyte is LiAlCl₄ or LiGaCl₄ dissolved in SO₂.

20. The electrochemical cell of claim 1 wherein said negative electrode has an initial discharge capacity of not greater than 120% of the positive electrode capacity.

7. A method of operating a rechargeable non-aqueous electrochemical cell, said cell comprising an alkali or alkaline earth metal negative electrode having an initial discharge capacity to a cell cut-off potential of 0.20 V of not greater than 150% of the positive electrode capacity, a positive electrode, a porous separator, and an SO₂ electrolyte solvent, comprising a dissolved electrolyte salt capable of being oxidized to produce a halogen and/or a Lewis acid on overcharge or overdischarge with voltage reversal, said method comprising the steps of:

(a) discharging said rechargeable cell to a sufficiently low positive potential approaching 0.00 V and for a sufficient time that said alkali or alkaline earth metal electrically connected to said negative electrode is at least 90% anodically dissolved; and

(b) less frequently than performing step (a), overdischarging said rechargeable cell into reversal for a sufficient coulombic capacity to reduce the state of charge of the positive electrode with respect to the state of charge of the negative electrode.

8. The method of claim 7 wherein the said cell is overdischarged in reversal about every 4 to 50 discharges.

9. The method of claim 7 wherein the said cell is overdischarged in reversal for a capacity in reversal less than the theoretical capacity of the positive electrode.

10. The method of claim 7 wherein said cell is resistively discharged starting from about 1.5 V to 0.3 V with a discharge cutoff positive potential approaching 0.00 V.

11. The method of claim 7 wherein the said negative electrode is lithium and the capacity in reversal is from about 1 to 20% of the theoretical capacity of the positive electrode.

12. The method of claim 7 wherein said negative electrode comprises lithium and the current density during reversal is less than 1.0 mA/cm².

13. The method of claim 7 wherein said positive electrode is CuCl₂, CuBr₂ or NiCl₂.

14. The method of claim 7 wherein said electrolyte salt is an aluminum halide salt or a gallium chloride salt.

15. A method of operating a rechargeable non-aqueous electrochemical cell, said cell comprising a lithium-ion negative electrode having an initial discharge capacity to a cell cut-off potential of about 0.20 V of not greater than 150% of the positive electrode capacity, a positive electrode containing at least 2 wt % of a carbonaceous conductive additive, a porous separator and an SO₂ electrolyte solvent comprising a dissolved electrolyte salt comprising a lithium cation, wherein said salt is capable of being oxidized to produce a halogen and/or a Lewis acid on overcharge or overdischarge with voltage reversal, said method comprising the steps of:

(a) discharging said rechargeable cell to a sufficiently low positive potential approaching 0.00 V and for a sufficient time that lithium metal deposits or lithium dendrites electrically connected to said negative electrode are at least 90% anodically dissolved; and

(b) less frequently than performing step (a), overdischarging said rechargeable cell into reversal for a sufficient coulombic capacity to reduce the state of charge of the positive electrode with respect to the state of charge of the negative electrode.

16. The method of claim 15 wherein the said electrolyte salt is an aluminum halide salt or a gallium halide salt.

17. The method of claim 15 wherein the said positive electrode is CuCl₂, CuBr₂ or NiCl₂.

18. The method of claim 15 wherein the said cell is resistively discharged starting from about 1.5 V to 0.3 V with a discharge cutoff positive potential approaching 0.00 V.

19. The method of claim 15 wherein the capacity passed during overdischarge in reversal is from about 0.2 to 20% of the theoretical capacity of the positive electrode.