High capacity cathode material with improved operating voltage

Patent metadata

Field	Value
Publication number	US-9825310-B2
Application number	US-201514697028-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Apr 25, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

The present invention relates to an electrochemical cell comprising an anode of a Group IA metal and a cathode of a composite material prepared from an aqueous mixture of iron sulfate, nickel sulfate, and sulfur. The cathode material of the present invention provides for a lithium electrochemical cell having an increased operating voltage and power performance with high discharge capacity as compared to a lithium cell comprising nickel disulfide cathode material. In addition, the cathode material of the present invention exhibits a smaller initial irreversible voltage loss as compared to iron disulfide. This makes the cathode material of the present invention particularly useful for implantable medical applications.

First claim

What is claimed is:

1. An electrochemical cell, comprising:
a) an anode of a Group IA metal;
b) a cathode comprising iron nickel disulfide having the general formula Fe x Ni 1-x S 2 , wherein 0.15≦x≦0.25;
c) a separator positioned between the anode and the cathode; and
d) an ionically conductive electrolyte activating the anode and the cathode.

2. The electrochemical cell of claim 1 wherein the cathode comprises a binder material.

3. The electrochemical cell of claim 2 wherein the binder material is a fluoro-resin powder.

4. The electrochemical cell of claim 1 wherein the cathode comprises a conductive additive material.

5. The electrochemical cell of claim 4 wherein the conductive additive material is selected from the group consisting of carbon, graphite, and a combination thereof.

6. An electrochemical cell, comprising:
a) an anode comprising lithium;
b) a cathode comprising a cathode active material of either Fe 0.15 Ni 0.85 S 2 or Fe 0.25 Ni 0.75 S 2 ;
c) a separator positioned between the anode and the cathode; and
d) an ionically conductive electrolyte activating the anode and the cathode.

7. The electrochemical cell of claim 6 wherein the cathode comprises a binder material.

8. The electrochemical cell of claim 7 wherein the binder material is a fluoro-resin powder.

9. The electrochemical cell of claim 6 wherein the cathode comprises a conductive additive material.

10. The electrochemical cell of claim 9 wherein the conductive additive material is selected from the group consisting of carbon, graphite, and a combination thereof.

11. The electrochemical cell of claim 6 wherein the electrolyte comprises a Group IA metal salt dissolved in a nonaqueous solvent.

12. The electrochemical cell of claim 11 wherein the nonaqueous solvent comprises an inorganic or organic solvent.

13. A method for making a cathode active material for an electrochemical cell, the method comprising the steps of:
a) selecting a first metal salt from the group consisting of iron sulfate (FeSO 4 ), iron acetate (Fe(C 2 H 3 O 2 ) 2 ), iron bromide (FeBr 3 ), iron perchlorate (Fe(ClO 4 ) 2 ), iron iodate (FeI 2 ), iron nitrate (Fe(NO 3 ) 3 ), iron oxalate (Fe(C 2 O 4 ) 3 ), iron thiocyanate (Fe(SCN) 3 ), and respective hydrate forms thereof;
b) selecting a second metal salt from the group consisting of nickel sulfate (NiSO 4 ), nickel chloride (NiCl 2 ), nickel formate (Ni(CHO 2 ) 2 ), nickel hypophosphite (Ni(H 2 PO 2 ) 2 ), and respective hydrate forms thereof;
c) mixing the first metal salt and the second metal salt with sulfur to thereby provide a metal salt matrix admixture; and
d) reacting the metal salt matrix admixture to provide the cathode active material having the general formula Fe x Ni 1-x S 2 , wherein 0.15≦x≦0.25.

14. The method of claim 13 including heating the metal salt matrix admixture to a temperature of from about 100° C. to 300° C.

15. The method of claim 13 including adding de-ionized water to the first metal salt and the second metal salt mixed with sulfur prior to reacting the resulting metal salt matrix admixture to provide the cathode active material.

Assignees

• Greatbatch Ltd

Inventors

• Palazzo Marcus J
• Shah Ashish

Classifications

• C01G49/009

  Compounds containing iron, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M4/5815

  Sulfides · CPC title

• H01M6/16

  with organic electrolyte (H01M6/18 takes precedence) · CPC title

• H01M4/405

  Alloys based on lithium · CPC title

• C01P2004/02

  obtained by optical microscopy · CPC title