Method for manufacturing positive electrode active material, and lithium ion battery

Patent metadata

Field	Value
Publication number	US-10985369-B2
Application number	US-202016893726-A
Country	US
Kind code	B2
Filing date	Jun 5, 2020
Priority date	May 18, 2016
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

A composite oxide with high diffusion rate of lithium is provided. Alternatively, a lithium-containing complex phosphate with high diffusion rate of lithium is provided. Alternatively, a positive electrode active material with high diffusion rate of lithium is provided. Alternatively, a lithium ion battery with high output is provided. Alternatively, a lithium ion battery that can be manufactured at low cost is provided. A positive electrode active material is formed through a first step of mixing a lithium compound, a phosphorus compound, and water, a second step of adjusting pH by adding a first aqueous solution to a first mixed solution formed in the first step, a third step of mixing an iron compound with a second mixed solution formed in the second step, a fourth step of performing heat treatment under a pressure more than or equal to 0.1 MPa and less than or equal to 2 MPa at a highest temperature more than 100° C. and less than or equal to 119° C. on a third mixed solution formed in the third step with a pH of more than or equal to 3.5 and less than or equal to 5.0.

First claim

What is claimed is:

1. A method for manufacturing a positive electrode active material comprising lithium, phosphorus, iron, and oxygen, comprising steps of:
forming a first mixed solution by mixing a lithium compound, a phosphorus compound, and a solvent;
forming a second mixed solution by adjusting pH by adding a first aqueous solution to the first mixed solution;
forming a third mixed solution by mixing an iron compound with the second mixed solution after the step of forming the second mixed solution; and
performing heat treatment on the third mixed solution,
wherein a pH of the third mixed solution is more than or equal to 3.5 and less than or equal to 5.0,
wherein a highest temperature in the heat treatment is more than 100° C. and less than or equal to 119° C.,
wherein a particle of the positive electrode active material comprises a surface and a thickness in a direction perpendicular to the surface,
wherein the thickness is more than or equal to 10 nm and less than or equal to 200 nm, and
wherein a length of the surface is 10 to 50 times the thickness.

2. The method for manufacturing a positive electrode active material according to claim 1 , wherein the solvent comprises water.

3. The method for manufacturing a positive electrode active material according to claim 1 , wherein the positive electrode active material has an olivine structure.

4. The method for manufacturing a positive electrode active material according to claim 1 , wherein an angle between the direction of the thickness and a direction of a b axis of the positive electrode active material is more than or equal to 0° and less than or equal to 20°.

5. The method for manufacturing a positive electrode active material according to claim 1 ,
wherein the lithium compound is a lithium chloride,
wherein the first aqueous solution is alkaline, and
wherein a base included in the first aqueous solution is ammonia or organic amine.

6. The method for manufacturing a positive electrode active material according to claim 1 , wherein the third mixed solution is formed in an air atmosphere.

7. A method for manufacturing a positive electrode active material comprising lithium, phosphorus, iron, and oxygen, comprising steps of:
forming a first mixed solution by mixing a lithium compound, a phosphorus compound, and a solvent;
forming a second mixed solution by adjusting pH by adding a first aqueous solution to the first mixed solution;
forming a third mixed solution by mixing an iron compound with the second mixed solution after the step of forming the second mixed solution; and
performing heat treatment on the third mixed solution,
wherein a pH of the third mixed solution is more than or equal to 3.5 and less than or equal to 5.0,
wherein a highest temperature in the heat treatment is more than 100° C. and less than or equal to 119° C.,
wherein a particle of the positive electrode active material comprises a surface and a thickness in a direction perpendicular to the surface,
wherein the thickness is more than or equal to 5 nm and less than or equal to 500 nm, and
wherein a length of the surface is 3 to 200 times the thickness.

8. The method for manufacturing a positive electrode active material according to claim 7 , wherein the solvent comprises water.

9. The method for manufacturing a positive electrode active material according to claim 7 , wherein the positive electrode active material has an olivine structure.

10. The method for manufacturing a positive electrode active material according to claim 7 , wherein an angle between the direction of the thickness and a direction of a b axis of the positive electrode active material is more than or equal to 0° and less than or equal to 20°.

11. The method for manufacturing a positive electrode active material according to claim 7 ,
wherein the lithium compound is a lithium chloride,
wherein the first aqueous solution is alkaline, and
wherein a base included in the first aqueous solution is ammonia or organic amine.

12. The method for manufacturing a positive electrode active material according to claim 7 , wherein the third mixed solution is formed in an air atmosphere.

Assignees

• Semiconductor Energy Lab

Inventors

• Miwa Takuya
• Yoneda Yumiko
• Oguni Teppei

Classifications

• H01M10/4235

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/362

  Composites · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• C01P2004/64

  Nanometer sized, i.e. from 1-100 nanometer · CPC title