Positive electrode active material, preparation method therefor and use thereof
View Patent ↗The present application provides a positive electrode active material, a preparation method therefor and the use thereof. The positive electrode active material may comprise a spinel lithium nickel manganese oxide material, wherein the spinel lithium nickel manganese oxide material has the following chemical formula: Li a Ni 0.5−x Mn 1.5−y M x+y O 4 , wherein M is selected from at least one of Mg, Zn, Ti, Zr, W, Nb, Al, B, P, Mo, V, or Cr, 0.9≤a≤1.1, −0.2≤x≤0.2, −0.02≤y≤0.3, and x+y≥0; the Mn 3+ content in the spinel lithium nickel manganese oxide material may be less than or equal to 0.7 wt %.
1 . A positive electrode active material comprising a spinel lithium nickel manganese oxide material, wherein the spinel lithium nickel manganese oxide material has a volume mean particle size between 2 μm to 24 μm and the following chemical formula: Li a Ni 0.5-x Mn 1.5-y M x+y O 4 , wherein M is selected from at least one of Mg, Zn, Ti, Zr, W, Nb, Al, B, P, Mo, V, or Cr, 0.9≤a≤1.1, −0.2≤x≤0.2, −0.02≤y≤0.3, and x+y≥0; and
a Mn 3+ content in the spinel lithium nickel manganese oxide material is 0.2 wt % to 0.7 wt %.
2 . The positive electrode active material according to claim 1 , wherein primary particles of the spinel lithium nickel manganese oxide material have a volume median particle size of 0.5 μm to 16 μm.
3 . The positive electrode active material according to claim 2 , wherein the primary particles of the spinel lithium nickel manganese oxide material have a volume median particle size of 2 μm to 10 μm.
4 . The positive electrode active material according to claim 1 , wherein the spinel lithium nickel manganese oxide material has a volume median particle size of 5 μm to 17 μm.
5 . The positive electrode active material according to claim 1 , wherein the spinel lithium nickel manganese oxide material is a single crystal-like or single crystal material.
6 . The positive electrode active material according to claim 1 , wherein primary particles of the spinel lithium nickel manganese oxide material have a morphology of octahedron or polyhedron.
7 . The positive electrode active material according to claim 1 , wherein in the spinel lithium nickel manganese oxide material, a molar ratio of Ni atoms and doping atoms at the position thereof to Mn atoms and doping atoms at the position thereof is greater than or equal to 1:3.
8 . The positive electrode active material according to claim 1 , further comprising a surface modification layer covering at least a part of a surface of the spinel lithium nickel manganese oxide material, and the surface modification layer comprises a material selected from at least one of Ti, Zr, W, Al, B, P, or Mo oxides.
9 . The positive electrode active material according to claim 8 , wherein a content of the surface modification layer is less than 3%, based on a total weight of the positive electrode active material.
10 . The positive electrode active material according to claim 1 , wherein the positive electrode active material is used to prepare a button half-cell, a charge capacity thereof at 3.5 V-4.4 V accounts for less than or equal to 2% of a charge capacity thereof at 3.5 V-4.9 V during a charge/discharge process at 0.01 C-0.2 C.
11 . A secondary battery, comprising the positive electrode active material according to claim 1 .
12 . A battery module, comprising the secondary battery according to claim 11 .
13 . A battery pack, comprising the battery module according to claim 12 .
14 . A power consuming device, comprising the secondary battery according to claim 11 .
15 . The positive electrode active material according to claim 1 , wherein primary particles of the spinel lithium nickel manganese oxide material have a volume median particle size of 1.1 μm to 16 μm.
16 . The positive electrode active material according to claim 1 , wherein the positive electrode active material is prepared by:
(1) providing a lithium source, a nickel source, a manganese source, and optionally an additive, and mixing powders thereof by ball milling to obtain a mixture;
(2) sintering the mixture in an atmosphere of air, oxygen or a mixture thereof, at a temperature of 850° C.-1150° C. for 2-50 hours;
(3) slowly cooling the mixture from the temperature for the sintering to 400° C.-650° C., wherein an average cooling rate of the slow cooling is ≤0.7° C./min; and
(4) cooling to room temperature to obtain the spinel lithium nickel manganese oxide material.