Positive electrode active material, method for manufacturing the same, and positive electrode containing the same

Abstract

The present invention relates to a single-particle positive electrode active material capable of realizing a battery having improved initial resistance characteristics and life characteristics, a method for producing the same, and a positive electrode including the same. The angle between the major axis of a crystal grain obtained by electron backscatter diffraction (EBSD) analysis and the lithium migration path is defined as α, and the angle is (cosα) 2 The present invention relates to a single-particulate positive electrode active material having a value of 0.5 or more, a method for producing the same, and a positive electrode containing the same.

Claims

1. When α is the angle between the major axis of a crystal grain and the lithium migration path obtained by electron backscatter diffraction (EBSD) analysis, (cosα) ２ The value is 0.5 or greater, It is a lithium composite transition metal oxide containing nickel (Ni), cobalt (Co), and manganese (Mn), A single-particle positive electrode active material consisting of 1 to 50 single crystal particles, wherein the single crystal particles have an average particle size (DEBSD) of 0.1 μm to 10 μm.

2. (A) A step of mixing a positive electrode active material precursor and a lithium raw material, and producing a plastic product by primary firing at a temperature of 800°C to 1000°C, and then producing a single-particulate lithium composite transition metal oxide by secondary firing of the plastic product at a temperature lower than the primary firing temperature, (B) The step of preparing a mixture by mixing the single-particulate lithium composite transition metal oxide and the cobalt raw material, (C) The step of heat-treating the mixture at a temperature of 650°C to 800°C, A method for producing a single-particulate positive electrode active material according to claim 1, including the method described in claim 1.

3. The method for producing a single-particulate positive electrode active material according to claim 2, wherein the primary calcination in step (A) is carried out under an oxygen atmosphere.

4. The method for producing a single-particulate positive electrode active material according to claim 2, wherein the secondary firing in step (A) is carried out at a temperature of 700°C to 900°C.

5. The method for producing a single-particulate positive electrode active material according to claim 2, wherein the secondary calcination in step (A) is carried out in an oxygen atmosphere.

6. The method for producing a single-particulate positive electrode active material according to claim 2, wherein in step (B), single-particulate lithium composite transition metal oxide and cobalt raw material are mixed in a molar ratio of 1:0.0001 to 0.

05.

7. The method for producing a single-particulate positive electrode active material according to claim 2, wherein the mixing in step (B) is dry mixing.

8. The method for producing a single-particulate positive electrode active material according to claim 2, wherein the heat treatment in step (C) is carried out in an oxygen atmosphere.

9. Current collector and, A positive electrode comprising a positive electrode active material layer located on the current collector, The positive electrode comprises the positive electrode active material layer containing the single-particulate positive electrode active material described in claim 1.

10. When θ is the angle between the lithium migration path of the single-particle positive electrode active material and the axis parallel to the upper surface of the current collector, (cosθ) ２ The positive electrode according to claim 9, wherein the value is 0.6 or greater.

11. The above (cosθ) ２ Value and (cos α) ２ The positive electrode according to claim 10, wherein the difference in values ​​is 0.2 or less.

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