Method for forming positive electrode active material

Patent metadata

Field	Value
Publication number	US-2025293251-A1
Application number	US-202318872436-A
Country	US
Kind code	A1
Filing date	Jun 16, 2023
Priority date	Jun 29, 2022
Publication date	Sep 18, 2025
Grant date	—

Abstract

A positive electrode active material that inhibits discharge capacity from decreasing during charge and discharge cycles is provided. Alternatively, a secondary battery with a high level of safety is provided. The secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode, and an electrolyte. The positive electrode active material is formed in the following manner: a first composite oxide containing lithium and cobalt, a magnesium source, and a fluoride are mixed to form a mixture; the mixture is heated at higher than or equal to 650° C. and lower than or equal to 1130° C. to form a second composite oxide; and the second composite oxide is cooled down at a temperature decreasing rate higher than 250° C./h.

First claim

1 . A method for forming a positive electrode active material, comprising:
a first step of mixing a first composite oxide comprising lithium and cobalt, a magnesium source, and a fluoride to form a mixture; a second step of heating the mixture to form a second composite oxide; and a third step of cooling down the second composite oxide, wherein the second step comprises a first process of performing temperature rising and a second process of retaining a temperature after the temperature rising, wherein the temperature retained in the second process is higher than or equal to 650° C. and lower than or equal to 1130° C., and wherein a temperature decreasing rate in the cooling is higher than 250° C./h.

2 . The method for forming a positive electrode active material, according to claim 1 ,
wherein the magnesium source is magnesium fluoride, and wherein the fluoride is lithium fluoride.

3 . The method for forming a positive electrode active material, according to claim 1 , wherein the cooling is performed in an oxygen atmosphere.

4 . The method for forming a positive electrode active material, according to claim 1 , wherein the second composite oxide is cooled down to lower than or equal to 100° C. by the cooling.

5 . A method for forming a positive electrode active material, comprising:
a first step of mixing a first composite oxide comprising lithium and cobalt, a magnesium source, and a fluorine source to form a first mixture; a second step of performing first heat treatment on the first mixture to form a second composite oxide; a third step of mixing the second composite oxide, a nickel source, and an aluminum source to form a second mixture; and a fourth step of performing second heat treatment on the second mixture to form a third composite oxide, wherein a heating temperature in the first heat treatment is higher than or equal to 650° C. and lower than or equal to 1130° C., wherein a heating temperature in the second heat treatment is higher than or equal to 650° C. and lower than or equal to 1130° C., wherein a temperature decreasing rate in the second heat treatment is higher than a temperature decreasing rate in the first heat treatment, and wherein the temperature decreasing rate in the second heat treatment is higher than 250° C./h.

6 . The method for forming a positive electrode active material, according to claim 5 ,
wherein the magnesium source is magnesium fluoride, and wherein the fluorine source is lithium fluoride.

7 . The method for forming a positive electrode active material, according to claim 5 ,
wherein the nickel source is nickel hydroxide, and wherein the aluminum source is aluminum hydroxide.

8 . The method for forming a positive electrode active material, according to claim 5 ,
wherein the magnesium source is magnesium fluoride, wherein the fluorine source is lithium fluoride, wherein the nickel source is nickel hydroxide, and wherein the aluminum source is aluminum hydroxide.

9 . The method for forming a positive electrode active material, according to claim 5 , wherein the third composite oxide is cooled down in an atmosphere comprising oxygen in the second heat treatment.

10 . The method for forming a positive electrode active material, according to claim 5 , wherein the third composite oxide is cooled down to lower than or equal to 100° C. in the second heat treatment.

11 . The method for forming a positive electrode active material, according to claim 9 , wherein the third composite oxide is cooled down to lower than or equal to 100° C. in the second heat treatment.

Assignees

• Semiconductor Energy Lab

Inventors

• Ochiai Teruaki
• Momma Yohei
• Suzuki Kunihiko
• Yamazaki Shunpei

Classifications

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• C01G51/42

  containing alkali metals, e.g. LiCoO2 · CPC title

• C01P2002/77

  by unit-cell parameters, atom positions or structure diagrams · CPC title