阅读说明：本技术 正极活性材料和锂离子电池 (Positive electrode active material and lithium ion battery ) 是由 曾巧 王可飞 于 2018-12-21 设计创作，主要内容包括：本申请提供一种正极活性材料、正极极片和锂离子电池。正极活性材料包括第一颗粒和第二颗粒,其中,第一颗粒的化学式为：Li<Sub>e</Sub>Co<Sub>g</Sub>M<Sub>1-</Sub><Sub>g</Sub>O<Sub>2-i</Sub>,所述第二颗粒的化学式为：Li<Sub>f</Sub>Co<Sub>h</Sub>N<Sub>1-h</Sub>O<Sub>2-j</Sub>,其中,M元素选自Ni、Mn、Al、Mg、Ti、La、Y和Zr中的至少两种,N元素选自Ni、Mn、Al、Mg、Ti、La、Y和Zr中的至少一种,且0.8≤e≤1.2、0<g<1、-0.1≤i≤0.2、0.8≤f≤1.2、0<h<1、-0.1≤j≤0.2,第一颗粒中的M元素的种类数大于第二颗粒中的N元素的种类数。通过调整第一颗粒和第二颗粒中掺杂元素的种类和含量,使得第一颗粒和第二颗粒稳定,提升锂离子电池的容量保持率。(The application provides a positive active material, a positive pole piece and a lithium ion battery. The positive electrode active material includes first particles and second particles, wherein the first particles have a chemical formula of: li e Co g M 1‑ g O 2‑i The second particle has the chemical formula: li f Co h N 1‑h O 2‑j Wherein, M element is selected from at least two of Ni, Mn, Al, Mg, Ti, La, Y and Zr, N element is selected from at least one of Ni, Mn, Al, Mg, Ti, La, Y and Zr, and e is more than or equal to 0.8 and less than or equal to 1.2 and 0<g<1、‑0.1≤i≤0.2、0.8≤f≤1.2、0<h<1. -0.1. ltoreq. j.ltoreq.0.2, the number of types of M elements in the first particles being greater than the number of types of N elements in the second particles. By adjusting the types and the contents of the doping elements in the first particles and the second particles, the first particles and the second particles are stable, and the capacity retention rate of the lithium ion battery is improved.)

A positive electrode active material comprising first particles and second particles, wherein the first particles have a chemical formula of: li_eCo_gM_1-gO_2-iThe second particle has the chemical formula: li_fCo_hN_1-hO_2-jWherein, M element is selected from at least two of Ni, Mn, Al, Mg, Ti, La, Y and Zr, N element is selected from at least one of Ni, Mn, Al, Mg, Ti, La, Y and Zr, and e is more than or equal to 0.8 and less than or equal to 1.2 and 0<g<1、-0.1≤i≤0.2、0.8≤f≤1.2、0<h<1. -0.1. ltoreq. j.ltoreq.0.2, the number of types of M elements in the first particles being greater than the number of types of N elements in the second particles.

The positive electrode active material according to claim 1, wherein the first particle has a chemical formula of: li_nCo_xM_1-xO_2-yThe second particle has the chemical formula: li_nCo_xN_1-xO_2-yWherein n is more than or equal to 0.8 and less than or equal to 1.2 and 0<x<1、-0.1≤y≤0.2。

The positive electrode active material according to claim 1, wherein a particle diameter of the first particles is smaller than a particle diameter of the second particles.

The cathode active material according to claim 3, wherein the first particles have a particle size smaller than Dv50 of the cathode active material, and the second particles have a particle size larger than Dv50 of the cathode active material.

The positive electrode active material according to claim 1, wherein a content of each of the M elements in the first particles is greater than 200ppm, and a content of each of the N elements in the second particles is greater than 200 ppm.

The positive electrode active material according to claim 1, wherein the positive electrode active material satisfies the following formula (1):

(a/b)/(c/d) >1 formula (1)

a represents the total mass of the M element in the first particles;

b represents the mass of the Co element in the first particles;

c represents the total mass of the N element in the second particles;

d represents the mass of the Co element in the second particles.

The positive electrode active material according to claim 1, wherein the positive electrode active material satisfies the following formula (2):

(A/B)/(C/D) >1 formula (2)

A represents the total molar amount of M element in the first particles;

b represents a molar amount of Co element in the first particles;

c represents the total molar amount of N element in the second particles;

d represents the molar amount of Co element in the second particles.

The positive electrode active material according to claim 6, wherein the positive electrode active material has a value of (a/b)/(c/d) of 1.3 to 10.

The cathode active material according to claim 1, wherein a volume-based particle size distribution curve of the cathode active material includes a first peak and a second peak.

The positive electrode active material according to claim 9, wherein a peak height of the second peak is greater than a peak height of the first peak.

The positive electrode active material according to claim 1, wherein a particle diameter of the positive electrode active material satisfies the following formula (3):

(Dv90-Dv50) - (Dv50-Dv10) 2.5 or less formula (3)

A positive electrode sheet comprising the positive electrode active material according to any one of claims 1 to 11.

The positive pole piece of claim 12, wherein the compacted density of the positive pole piece is greater than or equal to 3.9g/cm³。

A lithium ion battery comprising the positive electrode sheet of claim 12 or 13.