Method of Forming a Metal Phosphate Coated Cathode for Improved Cathode Material Safety

• US 20120164319A1
• Filed: 12/19/2011
• Published: 06/28/2012
• Est. Priority Date: 12/21/2010
• Status: Abandoned Application

• Current Assignee: Physical Sciences Incorporated
• Original Assignee: Physical Sciences Incorporated
• Inventors: Newman, Aron, Lang, Christopher M.
• Application Number:
  US13/329,839
• Publication Number:
  US 20120164319A1
• Time in Patent Office: Days
• US Class Current: 427/126.6
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The invention features a method of forming a metal phosphate coated cathode. Either a metal salt or a phosphate salt is dissolved in a nonaqueous solvent to form a first solution. The other of the metal salt or the phosphate salt (e.g., whichever compound is not dissolved in the nonaqueous solvent) is dissolved in a second solvent to form a second solution. The first solution and the second solution are mixed to form a precursor solution. A cathode material is added to the precursor solution to form a cathode-precursor solution. The cathode-precursor solution is dried to form the metal phosphate coated cathode.

Claims

1. A method of forming a metal phosphate coated cathode, comprising:

dissolving either a metal salt or a phosphate salt in a nonaqueous solvent to form a first solution;

dissolving the other of the metal salt or the phosphate salt in a second solvent to form a second solution;

mixing the first solution and the second solution to form a precursor solution;

adding a cathode material to the precursor solution to form a cathode-precursor solution; and

drying the cathode-precursor solution to form the metal phosphate coated cathode.

2. The method of claim 1 wherein the metal salt is dissolved in the nonaqueous solvent and the phosphate salt is dissolved in the second solvent.

3. The method of claim 1 wherein the metal salt and the phosphate salt are dissolved in nonaqueous solvent.

4. The method of claim 1 wherein the nonaqueous solvent is isopropanol.

5. The method of claim 1 wherein the metal salt is dissolved in isopropanol and the phosphate salt is dissolved in water.

6. The method of claim 1 wherein the nonaqueous solvent is N-methyl-2-pyrrolidone.

7. The method of claim 1 wherein the metal salt is dissolved in N-methyl-2-pyrrolidone and the phosphate salt is dissolved in water.

8. The method of claim 1 wherein the metal salt comprises at least one of cobalt nitrate;

cobalt acetate, cobalt sulfate, nickel nitrate, nickel acetate, and aluminum nitrate.

9. The method of claim 1 wherein the phosphate salt is ammonium hydrogen phosphate.

10. The method of claim 1 further comprising using a shear mixer to mix the first and second solutions.

11. The method of claim 1 wherein the cathode material is a cathode powder.

12. The method of claim 1 wherein the cathode material is a lithium metal oxide.

13. The method of claim 12 wherein the lithium metal oxide is lithium cobalt oxide.

14. The method of claim 12 wherein the lithium metal oxide is lithium nickel cobalt aluminum oxide.

15. The method of claim 12 wherein the lithium metal oxide is lithium nickel cobalt manganese oxide.

16. The method of claim 1 wherein the metal salt is a mixture of metal salts.