Granted Patent B2

US 12,665,187 · App. 17/906,450 · Granted Jun 23, 2026

Inventors: Kazuhei Narita (Tokyo, JP); Yohei Momma (Isehara, JP); Shunpei Yamazaki (Tokyo, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

H01M4/366C01G51/42C01G53/50H01M4/485H01M4/505H01M4/525

Abstract

Claims (26)

1 . A method for manufacturing a secondary battery comprising a positive electrode active material, the method comprising steps of:

forming a first mixture by mixing a first lithium source and a first transition metal source;

heating the first mixture to form a first composite oxide, wherein the heating of the first mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1100° C.;

forming a second mixture by mixing the first composite oxide and a first impurity source;

heating the second mixture to form the first composite oxide in which a first impurity layer is provided, wherein the heating of the second mixture is performed at a temperature higher than or equal to 830° C. and lower than or equal to 950° C.;

forming a third mixture by mixing the first composite oxide in which the first impurity layer is provided, a second lithium source, and a second transition metal source; and

heating the third mixture to form a second composite oxide over the first impurity layer, wherein the heating of the third mixture is performed at a temperature higher than or equal to 700° C. and lower than or equal to 900° C.,

wherein the first transition metal source and the second transition metal source are each at least one of a cobalt source, a nickel source, a manganese source, and an iron source.

2 . The method of manufacturing a secondary battery according to claim 1 ,

wherein a melting point of the first composite oxide is higher than a melting point of the second composite oxide, and

wherein the temperature of the heating of the third mixture is lower than the temperature of the heating of the first mixture by 100° C. or more.

3 . A method for manufacturing a secondary battery comprising a positive electrode active material, the method comprising steps of:

forming a first mixture by mixing a first lithium source and a first transition metal source;

heating the first mixture to form a first composite oxide, wherein the heating of the first mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1100° C.;

forming a second mixture by mixing the first composite oxide and a first impurity source;

heating the second mixture to form the first composite oxide in which a first impurity layer is provided, wherein the heating of the second mixture is performed at a temperature higher than or equal to 830° C. and lower than or equal to 950° C.;

forming a third mixture by mixing the first composite oxide in which the first impurity layer is provided, a second lithium source, and a second transition metal source;

heating the third mixture to form a second composite oxide over the first impurity layer, wherein the heating of the third mixture is performed at a temperature higher than or equal to 700° C. and lower than or equal to 900° C.;

forming a fourth mixture by mixing a second impurity source and the first composite oxide in which the first impurity layer and the second composite oxide are provided; and

heating the fourth mixture to form a second impurity layer over the second composite oxide,

wherein the first transition metal source and the second transition metal source are each at least one of a cobalt source, a nickel source, a manganese source, and an iron source,

wherein the first impurity source and the second impurity source are each at least one of a titanium source, a magnesium source, and a fluorine source, and

wherein the second impurity layer is positioned outside of the first impurity layer.

4 . The method of manufacturing a secondary battery according to claim 3 ,

wherein a melting point of the first composite oxide is higher than a melting point of the second composite oxide, and

wherein the temperature of the heating of the third mixture is lower than the temperature of the heating of the first mixture by 100° C. or more.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (139)