Method for improving voltage regulation of batteries, particularly Li/FeS.sub.2 thermal batteries

• US 4,761,487 A
• Filed: 06/10/1986
• Issued: 08/02/1988
• Est. Priority Date: 06/10/1986
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Department Of Energy
• Original Assignee: United States Department of Energy
• Inventors: Godshall, Ned A.
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Kalafut, Stephen J.
• Application Number:
  US06/872,718
• Time in Patent Office: 784 Days
• Field of Search: 429/112, 429/221, 252/182.1
• US Class Current: 429/112
• CPC Class Codes: H01M 4/581 Chalcogenides or intercalation compounds thereof
• CPC Class Codes: H01M 6/36 containing electrolyte and made operational by physical means, e.g. thermal cells

Abstract

Batteries are improved, especially with respect to voltage regulation properties, by employing as anode and cathode compositions, those which fall in a thermodynamically invariant region of the metallurgical phase diagram of the combination of the constituent components. The invention is especially useful in the Li/FeS₂ system.

Claims

1. In a battery composition useful as the cathode of a Li/FeS₂ thermal battery, consisting essentially of substantially pure FeS₂, the improvement wherein sufficient lithium is added to said composition whereby the resultant composition falls into a three-phase thermodynamically invariant region of the Li/Fe/S phase diagram and has the formula Li_x FeS₂ with the proviso that 0.05≦

x≦

1.5.

2. A substantially pure composition of the formula Li_x FeS₂, wherein x is a number sufficient to cause said composition to fall in a three-phase, thermodynamically invariant region of the Li/Fe/S metallurgical phase diagram and 0.05≦

x≦

1.5.

3. A composition of claim 2 substantially free of the cathodic discharge products formed during discharge of a Li/FeS₂ thermal battery.

4. In a Li/FeS₂ thermal battery comprising an anode and a cathode, the improvement wherein the cathode composition is of the formula Li_x FeS₂ with x being about 0.15 to about 0.75, which falls into a three phase thermodynamically invariant region of the Li/Fe/S phase diagram, wherein said lithium is added in the form of lithium metal or Li₂ S.