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

Abstract

The present invention comprises a lithium transition metal oxide in single-particle form, wherein the lithium transition metal oxide contains 60 mol% or more nickel of the total transition metal, and the positive electrode active material contains 6,500 kgf / cm². 2 This invention relates to a positive electrode active material in which, when pressure is applied, the content of fine particles with a particle size of 1 μm or less is 10% by volume or less, based on the total volume of the positive electrode active material, a method for producing the same, and a positive electrode and lithium secondary battery containing the same.

Claims

1. Containing lithium transition metal oxide in single-particle form, The lithium transition metal oxide contains 60 mol% or more of nickel among the total transition metals. 6,500 kgf / cm² applied to the positive electrode active material. ２ When pressure is applied, the content of fine particles with a particle size of 1 μm or less, based on the total volume of the positive electrode active material, is 10% by volume or less.

2. The positive electrode active material has an average particle size (D ５０ The positive electrode active material according to claim 1, wherein the diameter of the material is 2 μm or more and 12 μm or less.

3. The positive electrode active material has a particle strength of 500 MPa or more and 1,500 MPa or less. The particle strength (MPa) is a value obtained by taking a sample of lithium transition metal oxide particles, placing the sample on glass, and then measuring the force required to break the particles and cause the tip to touch the glass on which the sample is placed while applying a pressure of 100 mN to the sample with a tip. This is the positive electrode active material according to claim 1.

4. The positive electrode active material according to claim 1, wherein the positive electrode active material has a composition represented by the following chemical formula 1. [Chemical formula 1] Li ａ Ni ｘ Co ｙ M １ ｚ M ２ １－ｘ－ｙ－ｚ O ２ In the aforementioned chemical formula 1, M １ is one or more selected from the group consisting of Mn and Al, M ２ is one or more selected from the group consisting of B, Ba, Ce, Cr, F, Mg, V, Ti, Fe, Zr, Zn, Si, Y, Nb, Ga, Sn, Mo, W, P, S, Sr, Ta, La, and Hf. 1.0 ≤ a ≤ 1.3, 0.6 ≤ x < 1.0, 0 < y < 0.4, 0 < z < 0.4, and 0 ≤ 1 - x - y - z ≤ 0.

4.

5. The positive electrode active material according to claim 1, wherein the content of fine powder with a particle size of 1 μm or less before rolling is 0% or more and 1% or less, based on the total number of positive electrode active materials.

6. 1) A step of mixing a positive electrode active material precursor containing 60 mol% or more nickel of the total transition metals with a lithium-containing raw material, raising the temperature to the primary firing temperature, and performing primary firing to produce a calcined product, 2) The step of cooling the calcined product to room temperature, A method for producing a single-particle type positive electrode active material, comprising the steps of: 3) mixing the calcined product and a lithium-containing raw material, raising the temperature to a secondary calcination temperature, and performing secondary calcination to produce a lithium transition metal oxide in single-particle form, A method for producing a positive electrode active material, wherein the primary firing temperature is 850°C or higher and 950°C or lower, the secondary firing temperature is 800°C or higher and 850°C or lower, and the secondary firing temperature is lower than the primary firing temperature.

7. The method for producing a positive electrode active material according to claim 6, wherein the heating rate in step 1) and the heating rate in step 3) are each 4°C / min or more and 7°C / min or less.

8. The method for producing a positive electrode active material according to claim 6, further comprising the step of 2-1) crushing the calcined product before secondary calcination in step 3) above.

9. 3-1) A method for producing a positive electrode active material according to claim 6, further comprising the step of pulverizing the lithium transition metal oxide.

10. A positive electrode comprising the positive electrode active material described in any one of claims 1 to 5.

11. The positive electrode described in claim 10, The negative electrode and, A separator interposed between the positive electrode and the negative electrode, A lithium secondary battery containing an electrolyte.

Images