CN115995544A

CN115995544A - Boron zirconium compound, amorphous aluminum oxide modified high-nickel ternary positive electrode material and preparation method thereof

Info

Publication number: CN115995544A
Application number: CN202310223509.1A
Authority: CN
Inventors: 胡彬; 杨允杰; 李猷; 岳敏; 古佳茜
Original assignee: Huading Guolian Sichuan Power Battery Co ltd
Current assignee: Huading Guolian Sichuan Power Battery Co ltd
Priority date: 2023-03-09
Filing date: 2023-03-09
Publication date: 2023-04-21

Abstract

The invention relates to a boron-zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials. Solves the problem of high residual alkali content on the surface of the high-nickel ternary positive electrode material in the prior art. The chemical general formula of the high-nickel ternary positive electrode material is LiNi _x Co _y Mn _z B _a Zr _b Al _c PO ₂ In the formula, 0.6 is less than or equal tox is less than 1.0, y is more than 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z+a+b+c=1. The invention also provides a preparation method of the high-nickel ternary positive electrode material. The preparation method of the invention does not need to increase related equipment, saves water resources, avoids the consumption of lithium resources, is safe and environment-friendly, improves the utilization rate of the resources and has low cost consumption. And the prepared high-nickel ternary positive electrode material has high structure and thermal stability, and has the comprehensive excellent performances of high gram specific capacity, low DCIR growth, long-cycle performance, high-temperature storage performance and the like.

Description

Boron zirconium compound, amorphous aluminum oxide modified high-nickel ternary positive electrode material and preparation method thereof

Technical Field

The invention belongs to the technical field of positive electrode materials, and particularly relates to a boron-zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material and a preparation method thereof.

Background

A lithium ion battery is a secondary battery (rechargeable battery) that operates mainly by means of movement of lithium ions between a positive electrode and a negative electrode. In the situation that the global energy crisis and environmental pollution are increasingly prominent, lithium ion batteries are attracting attention as a novel green energy storage device. The method is widely applied to the fields of 3C digital codes, wearable products, electric tools, new energy automobiles and the like. Along with the rapid development of new energy automobiles, the demand of lithium ion batteries is also rapidly increased, and the demands of batteries with high energy density, low cost and high cost performance are also increasingly strong.

The ternary NCM, NCA, NCMA and other positive electrode materials are widely applied to lithium ion batteries as high-energy-density positive electrode materials. Co element is much lower than Ni/Mn/Al, belongs to rare metal elements, has certain radiation, and has high specific volume, high energy density and long endurance, so that the main melody and the user requirement of the new energy automobile are met. However, the increase in Ni content causes a problem that the DSC thermal decomposition temperature of the material decreases, the heat release amount increases, and the thermal stability deteriorates. And Ni content is increased, resulting in easier CO in the material surface and environment ₂ And H ₂ O reacts to generate LiOH and Li on the surface of the material ₂ CO ₃ LiOH and LiPF in electrolyte ₆ The reaction occurs to form HF, which causes dissolution of Ni and Mn under corrosion of HF and surface coating layer to be peeled off, resulting in a reduction in cycle/shelf life.In a charged high-voltage polarization or high-temperature storage state, li ₂ CO ₃ Can produce CO by reaction and decomposition ₂ 、CH ₄ Etc. Finally, the gradual increase of the nickel content leads to serious Li/Ni mixing discharge, unsatisfactory cycle and storage life and the like.

In order to further improve the cycle and storage life of the high-nickel ternary cathode material, reduce Li/Ni mixed discharge and reduce residual alkali on the surface of the high-nickel ternary cathode material, in the prior art, a water washing (wet method) method is generally adopted to reduce the residual alkali content on the surface of the high-nickel ternary cathode material. Although the water washing method can effectively reduce the residual alkali on the surface of the high-nickel ternary cathode material, the gram specific capacity of the high-nickel ternary cathode material can be reduced, and the cycle performance can be reduced. Because the high-nickel ternary positive electrode material is sensitive to water, li on the surface of the material in the long-time water washing process ⁺ And the water is easy to dissolve, a replacement process can exist during dissolution, and water molecules can slowly enter the grain boundary region of the electrode material particles, so that the water cannot be fully removed during later drying, and the electrochemical performance of the material is affected. In addition, according to the material with Ni more than or equal to 80, the water-material ratio of the water washing process is 1:1 or more, the consumption ratio of pure water is more than or equal to 1, the investment cost of related pure water preparation, water washing, pressure filtration and drying equipment and wastewater purification treatment equipment is increased by one ton of raw material cost, and the process flow time is increased by 40% in a same ratio. In addition, the recovery rate of Li in the water washing process is low, the difficulty is high, and the investment is high. Researchers find that, in addition to the commonly used cationic metal modification, the use of boron compounds such as boron oxide or boric acid, or boron-doped compounds as a coating layer, can act as an insulating electrolyte, which is beneficial to improving the cycle performance of the cathode material. For example, in a high-capacity nickel cobalt lithium manganate-based composite positive electrode material and a preparation method thereof (publication number CN 108899502A), after one-step water washing, boron is coated on the surface of the positive electrode material by two-step water washing, so that the surface structure of the material can be improved, the interface stability can be improved, and the cycle performance can be improved. However, boron coats the surface of the material, and the generation of microcracks and the breakage of particles during high-temperature storage and circulation cannot be avoided. Particle breakage can exacerbate gas production of lithium ion batteries, and the gas production can lead to soft-package lithium ion batteries Inflation occurs; the generated bubbles accumulate inside the battery cells and can also cause lithium precipitation at the edges of the bubbles. Therefore, the performance of the material cannot be improved to a great extent by a single type element, so that the composite doping and gradient cladding are one of the effective measures at present.

In the prior art, yu Chunlin et al provide a scheme for preparing a ternary precursor by doping B element and a subsequent preparation method in a high-nickel ternary precursor material doped with boron element of China patent, a preparation method thereof and a high-nickel ternary cathode material (publication No. CN 114988494A), and the molecular formula of the high-nickel ternary precursor material is as follows: ni (Ni) _a Co _b Mn _c (OH) ₂ ·(BO ₂ ) _d The method comprises the steps of carrying out a first treatment on the surface of the Wherein a is more than or equal to 0.8<1、0<b≤0.15、0<c is less than or equal to 0.05, and a+b+c=1; 0<d is less than or equal to 0.05; the inner core of the high-nickel ternary precursor material is in a compact stacking structure, the outer shell is in a dendritic radiation loose structure, and the core-shell of the high-nickel ternary precursor material has the uniform doping of B element. According to the scheme, doping elements are added in the preparation process of the precursor material, so that the uniformity of the doping elements is ensured, the obtained precursor material has good high-temperature stability, and the fully-radial anode material with excellent performance can be obtained through high-temperature sintering control. For example, zhang Bao et al provide a scheme and a subsequent preparation method of a ternary precursor co-doped with Zr and polyanion in a ternary positive electrode material (CN 113764647A) prepared from a ternary positive electrode material precursor modified by doping zirconium and polyanion and a preparation method thereof; the method provides a zirconium and polyanion doped modified ternary positive electrode material precursor, which comprises a ternary positive electrode material precursor body and a zirconium dioxide modification layer on the surface of the precursor body, wherein Zr elements and polyanion elements are uniformly distributed in a bulk phase structure of precursor particles. The anode material has uniformly distributed doping elements, good structural stability and Li ⁺ The preparation method has the advantages of low transmission potential barrier, good electrochemical performance, short process flow and outstanding social benefit, and is suitable for popularization and application. He Lipo et al provide a Zr-doped ternary precursor scheme and a subsequent preparation method in a zirconium-doped nickel-cobalt-manganese ternary material and a preparation method thereof (CN 109659555A), and the method mainly comprises the following steps: comprising the following steps: will beAfter the positive plate obtained by disassembling the retired lithium ion battery is processed, the lithium-containing battery is obtained ⁺ 、Ni ²⁺ 、Co ²⁺ 、Mn ²⁺ And Zr (Zr) ²⁺ Is added to the leaching solution; regulating the contents of nickel, cobalt, manganese and zirconium elements in the leaching solution to obtain a raw material solution for synthesizing a zirconium-doped nickel-cobalt-manganese ternary precursor; synthesizing a zirconium-doped ternary material precursor and a lithium-containing solution by using a raw material solution; concentrating the lithium-containing solution by a certain multiple, and recovering lithium salt in the solution by adopting a precipitation method; preheating a zirconium-doped nickel-cobalt-manganese ternary precursor at a high temperature to obtain a zirconium-doped ternary material intermediate; and uniformly mixing the intermediate with lithium salt, and performing high-temperature solid-phase reaction to obtain the zirconium-doped nickel-cobalt-manganese ternary material. The preparation method realizes the recycling of nickel, cobalt, manganese and zirconium elements in the retired lithium ion battery, and improves the electrochemical performance of the nickel-cobalt-manganese ternary material. The methods adopt the method that the B or Zr element salt compound is added at the precursor end to react to prepare the precursor, so that the reaction synthesis difficulty of the precursor is increased to a certain extent, and the later reaction difficulty of impurity elements is increased; meanwhile, the elements belong to a single type, and the reflected effect is not outstanding; in the later stage, similar elements are still required to be added at the ternary preparation end to further modify the performance of the high-nickel ternary positive electrode material, and the problems of high preparation cost of the front-end material and the like exist.

Disclosure of Invention

The invention aims to provide a boron-zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material which has the comprehensive excellent performances of long cycle, high-temperature multiplying power, high gram specific capacity, low DCIR growth and the like.

The second object of the invention is to provide a preparation method of the boron zirconium compound and the amorphous aluminum oxide modified high-nickel ternary cathode material, which solves the problem of high residual alkali content on the surface of the high-nickel ternary cathode material in the prior art without adding related equipment, saves water resources, avoids water resource pollution, environmental pollution and lithium resource consumption caused by precipitation of metal elements during water washing, further improves the utilization rate of resources, and has low cost consumption.

The technical scheme adopted by the invention for achieving the purpose is as follows.

The invention provides a boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material, the chemical formula of which is LiNi _x Co _y Mn _z B _a Zr _b Al _c PO ₂ Wherein x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z+a+b+c=1;

the invention also provides a preparation method of the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary anode material, which comprises the following steps:

Step one, uniformly mixing a high-nickel ternary precursor, a lithium source and a doping compound, and then sintering the mixture for the first time in an oxygen or oxygen-air atmosphere, cooling, crushing, sieving and demagnetizing to obtain a high-nickel ternary positive electrode material substrate;

the chemical formula of the high-nickel ternary precursor is Ni _x Co _y Mn _z (OH) ₂ Wherein x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z=1;

the doped compound is ZrB ₂ Amorphous Al ₂ O ₃ ，ZrB ₂ Is in a hexagonal crystal form, the purity is more than or equal to 99 percent, and the amorphous Al ₂ O ₃ Is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ One or more of the high nickel ternary precursors, li in lithium source ⁺ The molar ratio of the total doping elements in the doping compound is 1: (0.96-1.10): (0.0001-0.01), high nickel ternary precursor and ZrB ₂ The mass ratio of (2) is 100:

(0.05-0.60), high nickel ternary precursor and amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.10 to 0.50);

the conditions of the primary sintering are as follows: the temperature is raised to 400-460 ℃ for 2-6 h at a temperature raising rate of 1-5 ℃/min, the temperature is raised to 580-740 ℃ for 2-5 h at the second stage, and the temperature is raised to 740-970 ℃ for 6-24 h at the third stage; or, at the heating rate of 1-30 ℃/h, the first stage is heated to 400-460 ℃ and kept for 2-6 h, the second stage is heated to 580-740 ℃ and kept for 2-5 h, and the third stage is heated to 740-970 ℃ and kept for 6-24 h;

Step two, washing the high-nickel ternary positive electrode material substrate prepared in the step one with water, and drying to obtain a washed and dried high-nickel ternary positive electrode material substrate;

step three, washing and drying the high-nickel ternary positive electrode material substrate and ZrB ₂ Amorphous Al ₂ O ₃ Uniformly mixing, performing secondary calcination in an oxygen or oxygen-air atmosphere, cooling, crushing, sieving and demagnetizing to obtain a secondary calcined high-nickel ternary positive electrode material substrate;

the ZrB ₂ Is in a hexagonal crystal form, the purity is more than or equal to 99 percent, and the amorphous Al ₂ O ₃ Is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ One or more of the high nickel ternary positive electrode material substrate and ZrB which are washed and dried ₂ The mass ratio of (2) is 100: (0.05-0.30), washing and drying the high nickel ternary positive electrode material base material and the amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.08-0.25);

the conditions of the secondary calcination are as follows: raising the temperature to 350-720 ℃ at a heating rate of 1-20 ℃/H, and preserving heat for 1-24H;

step four, secondary calcination of the high-nickel ternary positive electrode material substrate and LiPO ₃ The mass ratio is 100: (0.2-1.3) mixing and coating, and calcining the obtained coating product for three times in an oxygen or oxygen-air atmosphere, cooling, crushing, sieving and demagnetizing to obtain a three-time calcined high-nickel ternary positive electrode material substrate;

the conditions of the three times of calcination are as follows: raising the temperature to 200-400 ℃ at a heating rate of 1-20 ℃/H, and preserving heat for 1-10H;

Step five, carrying out low-temperature batch mixing on the three-time calcined high-nickel ternary positive electrode material base material under the dehydration and decarbonation gas or inert atmosphere to obtain a boron-zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material;

the conditions of the low-temperature batch mixing are as follows: mixing materials for 0.5-6 h at the temperature rising rate of 1-5 ℃/min to 100-200 ℃ and replacing every 0.5-1.0 h.

Preferably, in the first step, the high nickel ternary precursor, li in the lithium source ⁺ The molar ratio of the total doping elements in the doping compound is 1: (0.98-1.08): (0.0003-0.008), high nickel ternary positive electrode material precursor and ZrB ₂ The mass ratio of (2) is 100: (0.1-0.45), high nickel ternary positive electrode material precursor and amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.15-0.40); more preferably, the high nickel ternary precursor, li in lithium source ⁺ The molar ratio of the total doping elements in the doping compound is 1: (0.99-1.05): (0.0012-0.0060), high nickel ternary positive electrode material precursor and ZrB ₂ The mass ratio of (2) is 100: (0.18-0.40), high nickel ternary positive electrode material precursor and amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.20-0.38).

Preferably, in the first and third steps, the ZrB ₂ The purity is more than or equal to 99 percent, and the grain diameter is 1-15 mu m; more preferably, the particle diameter is 2 to 4. Mu.m.

More preferably, the method comprises the following steps: uniformly mixing zirconium metal, boron carbide and boron nitride, and heating and firing in an inert atmosphere to obtain ZrB with purity of more than or equal to 99% and hexagonal crystal form ₂ The block is decarburized, cooled and crushed to obtain ZrB ₂ 。

Particularly preferably, the inert atmosphere is argon or hydrogen, the heating firing temperature is 2000 ℃, the time is 4-8 h, and the decarburization process is as follows: and (3) preserving the temperature for 12h at 350 ℃ in an oxidizing atmosphere.

Preferably, in the first step, the high-nickel ternary precursor is a small-particle high-nickel ternary precursor or a large-particle high-nickel ternary precursor, the particle size of the small-particle high-nickel ternary precursor is 2-6 μm, and the particle size of the large-particle high-nickel ternary precursor is 7-15 μm; more preferably, the particle size of the small-particle high-nickel ternary precursor is 3.0-5.0 mu m, and the particle size of the large-particle high-nickel ternary precursor is 9-12 mu m;

more preferably, the high-nickel ternary precursor in the first step is a large-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 8-16 μm, and the particle size of the prepared high-nickel ternary positive electrode material is 8-16 μm; particularly preferably, the particle size of the prepared high-nickel ternary positive electrode material substrate is 9-12 mu m, and the particle size of the prepared high-nickel ternary positive electrode material is 9-12 mu m;

More preferably, the high-nickel ternary precursor in the first step is a small-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 2.5-6.0 μm, and the particle size of the prepared high-nickel ternary positive electrode material is 2.5-6.0 μm; particularly preferably, the particle size of the prepared high-nickel ternary positive electrode material substrate is 3.0-5.0 mu m, and the particle size of the prepared high-nickel ternary positive electrode material is 3.0-5.0 mu m; most preferably, the particle size of the prepared high nickel ternary cathode material is 3.5-4.5 mu m.

Preferably, in the first step, the lithium source is LiOH, liOH.H ₂ O、Li ₂ CO ₃ And LiNO ₃ One or more of the following; more preferably, the lithium source is LiOH H ₂ O、Li ₂ CO ₃ One or two of them.

Preferably, in the first step, the particle size of the lithium source is 4 to 10 μm.

Preferably, in the first and third steps, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (0-80): (0-80): (0-80): (0-10); more preferably, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (1) is (10-60): (10-60): (5-70): (2-8), particularly preferred is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (20-50): (20-50): (20-70): (3-6).

Preferably, in the first step, the equipment used for uniform mixing is a ball mill, a tank mill, a coulter mixer or a high-speed mixer; more preferably, the equipment used for uniform mixing is a ball mill, a coulter mixer or a high-speed mixer.

Preferably, in the first step, the equipment adopted in the primary sintering is a muffle furnace or a tube furnace, and the primary sintering conditions are as follows: the temperature is raised to 420-460 ℃ for 3-5 h at a temperature raising rate of 2-4 ℃/min, the temperature is raised to 620-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage; more preferably, the temperature is raised to 420-460 ℃ for 4h at a temperature raising rate of 3 ℃/min, the temperature is raised to 640-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 10-18 h at the third stage.

Preferably, in the first step, the equipment adopted in the primary sintering is an atmosphere roller kiln or a rotary kiln, and the primary sintering conditions are as follows: the temperature is raised to 420-460 ℃ for 3-5 h at a temperature raising rate of 5-20 ℃/h, the temperature is raised to 620-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage; more preferably, the temperature is raised to 420-460 ℃ for 4h at a heating rate of 10 ℃/h, the temperature is raised to 640-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 10-18 h at the third stage.

Preferably, in the first step and the third step, the oxygen concentration is more than or equal to 95%.

Preferably, in the second step, the conditions of the water washing are as follows: the mass ratio of the material to the water is 1: (0.5-3.0), the time is 10-120 s, filter pressing and pre-dehydration are carried out in the water washing process, nitrogen is introduced into the filter after the pre-dehydration is finished to purge for 1-4H, and the water content of a filter cake is controlled to be less than or equal to 7%; more preferably, the mass ratio of the material to the water is 1 (1.0-2.0), the time is 20-60 s, and the nitrogen is purged for 2-3H; it is particularly preferred that the mass ratio of material to water is 1:1.5 for 30 seconds.

Preferably, in the second step, the drying temperature is 120-200 ℃ and the drying time is 1-12 h; more preferably, the drying temperature is 130-180 ℃ and the drying time is 3-10 h; particularly preferably, the drying temperature is 150 to 160 ℃ and the drying time is 4 to 8 hours.

Preferably, in the third step, the high nickel ternary positive electrode material substrate and ZrB are washed and dried ₂ The mass ratio of (2) is 100: (0.10-0.25), washing and drying the high nickel ternary positive electrode material base material and the amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.10 to 0.22); betterOptionally, washing and drying the high-nickel ternary positive electrode material substrate and ZrB ₂ The mass ratio of (2) is 100: (0.12-0.20), washing and drying the high nickel ternary positive electrode material base material and the amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.12-0.20).

Preferably, in the third step, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (0-80): (0-80): (0-80): (0-10); more preferably, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (1) is (10-60): (10-60): (5-70): (2-8), particularly preferred is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (20-50): (20-50): (20-70): (3-6).

Preferably, in the third step, the condition of the secondary calcination is as follows: raising the temperature to 400-680 ℃ at a heating rate of 1-20 ℃/H, and preserving heat for 3-14H; more preferably, the temperature is raised to 420-580 ℃ at a heating rate of 1-20 ℃/H for 6-11H.

Preferably, in the third step, the equipment for uniform mixing adopts a high-speed mixer and a mechanical fusion machine; more preferably, the apparatus used for uniform mixing is a high-speed mixer.

Preferably, in the fourth step, the high nickel ternary cathode material substrate and LiPO are subjected to secondary calcination ₃ The mass ratio of (2) is 100: (0.3-1.0); more preferably, the secondary calcination of the high nickel ternary positive electrode material substrate and LiPO ₃ The mass ratio of (2) is 100: (0.4-0.8).

Preferably, in the fourth step, the conditions of the third calcination are as follows: raising the temperature to 240-385 ℃ at a heating rate of 1-20 ℃/H, and preserving the heat for 3-8H; more preferably, the temperature is raised to 300-380 ℃ at a heating rate of 1-20 ℃/H for 4-7H.

Preferably, in the fifth step, the conditions of low-temperature batch mixing are as follows: heating to 120-180 ℃ at a heating rate of 1-4 ℃/min, mixing for 2.0-5.0 h, and replacing every 0.5-1.0 h; more preferably, the mixture is mixed for 3.0 to 4.0 hours at a temperature rising rate of 2 to 3 ℃/min to 140 to 160 ℃ and replaced every 0.5 to 1.0 hour.

The preparation method of the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material comprises the following steps:

first, by using ZrB ₂ Hexagonal crystal structure, DSC stability characteristics, amorphous Al ₂ O ₃ The comprehensive characteristics of atoms and ion crystals are that B/Zr/Al is co-doped through a high-temperature one-firing solid phase method reaction, so that the structure and the thermal stability of the nickel-cobalt-manganese ternary positive electrode material are improved, and microcracks of the structure of the high-nickel material are reduced; the ion channel and the interlayer distance are widened, and the discharge efficiency and the multiplying power capability of the material are improved; the Li/Ni mixed discharge degree and the particle surface energy are reduced;

secondly, by optimizing a lithium proportion and a doping element formula system and adopting a three-section one-firing process mode, the Li/Ni mixed discharge degree of the high-nickel ternary cathode material is reduced, the radial growth of particles is optimized, and DCIR is reduced;

thirdly, cleaning by deionized water to reduce residual alkali on the surfaces of the particles and reduce certain alkali content on the surfaces;

fourth, through ZrB ₂ Amorphous Al ₂ O ₃ Mixing with the obtained Ni/Co/Mn/B/Zr/Al oxide matrix, and calcining for the second time to form B/Zr/Al coating improvement to reduce contact between the positive electrode material and electrolyte and eliminate Li on the surface of the material ₂ CO ₃ Residual alkali is removed, so that the occurrence of interface side reaction is inhibited; the surface electron conductivity is improved, and the first discharge efficiency is improved; the structure and the circulation stability of the material are improved;

fifth, by introducing LiPO ₃ The secondary coating and the tertiary low-temperature calcination processes form gradient coating, block moisture reaction, reduce surface residual alkali, repair particle surface characteristics, further improve surface conductivity, reduce surface waterproof blocking capacity, form a surface coating protective layer, further improve surface side reaction and improve cycle performance;

Sixthly, the moisture absorbed by the surface particles in the process is further removed through low-temperature batch mixing, so that the reaction of residual alkali on the surface is inhibited, and the loss of the dry materials and the irreversible reaction in the later period can be reduced.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method of the boron zirconium compound and the amorphous aluminum oxide modified high-nickel ternary cathode material does not need to increase related equipment, saves water resources, avoids the consumption of lithium resources, is safe and environment-friendly, improves the utilization rate of the resources and has low cost consumption. And the prepared boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material has high structure and thermal stability, and has the comprehensive excellent performances of higher gram specific capacity, low DCIR growth, long-cycle performance, high-temperature storage performance and the like.

Drawings

In order to more clearly illustrate the technical solutions of the examples of the present invention, the drawings needed in the examples will be briefly described below, it being obvious that the drawings in the following description are only some examples of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a cycle chart of the high nickel ternary positive electrode materials of examples 1-2 and comparative examples 1-2 of the present invention;

FIG. 2 is a graph showing the cycle of the high nickel ternary positive electrode materials of examples 3 to 4 and comparative examples 3 to 4 of the present invention;

FIG. 3 is a graph showing the cycle of the high nickel ternary positive electrode materials of examples 5 to 6 and comparative examples 5 to 6 of the present invention;

FIG. 4 is SEM topographical features of the high nickel ternary cathode materials of examples 1-6 of the present invention;

FIG. 5 is a graph of the full cell cycle of the high nickel ternary of example 1 and comparative example 1 of the present invention;

fig. 6 is a schematic process flow diagram of a method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary positive electrode material of the present invention.

Detailed Description

For a further understanding of the present invention, preferred embodiments of the invention are described below, but it is to be understood that these descriptions are merely intended to illustrate further features and advantages of the invention, and are not limiting of the claims of the invention.

The invention relates to a boron zirconium compound and an amorphous aluminum oxide modified high-nickel ternary positive electrode material, wherein the chemical formula of the high-nickel ternary positive electrode material is LiNi _x Co _y Mn _z B _a Zr _b Al _c PO ₂ Wherein x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z+a+b+c=1.

As shown in fig. 6, the preparation method of the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary cathode material comprises the following steps:

Step one, a high nickel ternary precursor, a lithium source (typically a lithium salt) and a dopant compound (ZrB) ₂ Amorphous Al ₂ O ₃ The additive 1) is uniformly mixed, and then is sintered for the first time in oxygen or oxygen-air atmosphere, cooled, crushed (coarse and fine), sieved and demagnetized to obtain a high-nickel ternary positive electrode material substrate;

step four, according to the mass ratio of 100: (0.2-1.3), the secondary calcined high nickel ternary positive electrode material base material and LiPO ₃ Mixing and coating, and calcining the obtained coating product for three times under the oxygen or oxygen-air atmosphere, cooling, crushing, sieving and demagnetizing to obtain a three-time calcined high-nickel ternary positive electrode material substrate;

and fifthly, carrying out low-temperature batch mixing on the three-time calcined high-nickel ternary positive electrode material base material under the dehydration and decarbonation gas or inert atmosphere to obtain the boron-zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material.

The steps are as followsIn the first step, the chemical formula of the high-nickel ternary precursor is Ni _x Co _y Mn _z (OH) ₂ Wherein x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z=1. The high-nickel ternary precursor is one or a mixture of two of a small-particle high-nickel ternary precursor and a large-particle high-nickel ternary precursor, the particle size of the small-particle high-nickel ternary precursor is 2-6 mu m, and the particle size of the large-particle high-nickel ternary precursor is 7-15 mu m; preferably, the particle size of the small-particle high-nickel ternary precursor is 3.0-5.0 mu m, and the particle size of the large-particle high-nickel ternary precursor is 9-12 mu m.

In the first step, the lithium source is preferably LiOH, liOH.H ₂ O、Li ₂ CO ₃ And LiNO ₃ One or more of the following; more preferably LiOH H ₂ O、Li ₂ CO ₃ One or two of them. The particle size of the lithium source is 4-10 μm, and the lithium source can be obtained by mechanically grinding and crushing coarse-particle lithium sources or selecting lithium sources with the specifications of the market.

In the first step, amorphous Al ₂ O ₃ Is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ One or more of the following; preferably delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (0-80): (0-80): (0-80): (0-10); more preferably, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (1) is (10-60): (10-60): (5-70): (2-8), particularly preferably, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (20-50): (20-50): (20-70): (3-6).

In the first step, zrB ₂ The purity is more than or equal to 99 percent, the crystal is in a hexagonal crystal form, and the grain diameter is 1-15 mu m. ZrB ₂ Can be prepared by the following method, but is not limited thereto, and can also be obtained commercially. Zirconium and boron carbide as metalsMixing with boron nitride uniformly, heating and firing under inert atmosphere to obtain hexagonal crystal form ZrB with purity more than or equal to 99% ₂ The block is decarburized, cooled and crushed to 1 to 15 mu m to obtain ZrB ₂ The method comprises the steps of carrying out a first treatment on the surface of the Preferably, the inert atmosphere is argon or hydrogen, the heating and firing temperature is 2000 ℃, the time is 4-8 h, and the decarburization process is as follows: preserving heat for 12h at 350 ℃ in an oxidizing atmosphere; the equipment commonly used for comminution is a mill. Reaction chemical formula 3ZrO ₂ +B ₄ C+8C+B ₂ O ₃ ＝3ZrB ₂ +9CO↑。

In the first step, the high-nickel ternary precursor and Li in the lithium source ⁺ The molar ratio of the total doping elements (Zr, B and Al) in the doping compound is 1: (0.96-1.10): (0.0001 to 0.01), preferably 1: (0.98-1.08): (0.0003 to 0.008), more preferably 1: (0.99-1.05): (0.0012 to 0.0060); high nickel ternary positive electrode material precursor and ZrB ₂ The mass ratio of (2) is 100: (0.05 to 0.60), preferably 100: (0.1 to 0.45), more preferably 100: (0.15-0.40); high nickel ternary positive electrode material precursor and amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.10 to 0.50), preferably 100: (0.15 to 0.40), more preferably 100: (0.20-0.38).

In the first step, the equipment for uniformly mixing is mixing equipment such as a ball mill, a tank mill, a coulter mixer, a high-speed mixer and the like; preferably a ball mill, a coulter mixer, a high speed mixer.

In the first step, the oxygen concentration is preferably not less than 95%.

In the first step, there are two modes for one sintering:

the equipment adopted in the primary sintering mode is a muffle furnace or a tube furnace, the temperature is raised to 400-460 ℃ for 2-6 h at the temperature raising rate of 1-5 ℃/min, the temperature is raised to 580-740 ℃ for 2-5 h at the second stage, and the temperature is raised to 740-970 ℃ for 6-24 h at the third stage; preferably, the temperature is raised to 420-460 ℃ for 3-5 h at a temperature raising rate of 2-4 ℃/min, the temperature is raised to 620-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage; more preferably, the temperature is raised to 420-460 ℃ for 4 hours at the first stage at a temperature raising rate of 3 ℃/min, the temperature is raised to 640-740 ℃ for 3-4 hours at the second stage, and the temperature is raised to 740-970 ℃ for 10-18 hours at the third stage;

another device adopted by the primary sintering is an atmosphere roller kiln or a rotary kiln, the temperature is raised to 400-460 ℃ for 2-6 h at the temperature raising rate of 1-30 ℃/h, the temperature is raised to 580-740 ℃ for 2-5 h at the second stage, and the temperature is raised to 740-970 ℃ for 6-24 h at the third stage; preferably, the temperature is raised to 420-460 ℃ for 3-5 h at a temperature raising rate of 5-20 ℃/h, the temperature is raised to 620-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage; more preferably, the temperature is raised to 420-460 ℃ for 4h at the temperature raising rate of 10 ℃/h, the temperature is raised to 640-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 10-18 h at the third stage.

In the first step, the high-nickel ternary precursor is a large-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 8-16 μm, preferably 9-12 μm, and the particle size of the high-nickel ternary positive electrode material is 8-16 μm, preferably 9-12 μm; when the high-nickel ternary precursor is a small-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 2.5-6.0 mu m, preferably 3.0-5.0 mu m, and the particle size of the high-nickel ternary positive electrode material is 2.5-6.0 mu m, preferably 3.0-5.0 mu m; more preferably 3.5 to 4.5. Mu.m.

In the second step, the equipment used for washing is usually a disperser, and the preferable conditions for washing are: water=1:0.5-3.0, time is 10-120 s, the water washing process is gradually injected into a plate-and-frame filter press to carry out filter pressing and pre-dehydration, nitrogen is introduced into the filter press to purge for 1-4H after the pre-dehydration is finished, and the water content of a filter cake is controlled to be less than or equal to 7%; more preferably, the material: water=1:1.0-2.0, time is 20-60 s, nitrogen is purged for 2-3H; particularly preferably, the material: water=1:1.5, time 30s.

In the second step, the drying device is usually a vacuum oven or a double cone dryer, preferably the drying temperature is 120-200 ℃ and the drying time is 1-12 h; more preferably, the drying temperature is 130-180 ℃ and the drying time is 3-10 hours; particularly preferably, the drying temperature is 150-160 ℃ and the drying time is 4-8 h.

In the third step, the high nickel ternary positive electrode material substrate and ZrB which are washed and dried ₂ The mass ratio of (2) is 100: (0.05 to 0.30), preferably 100: (0.1 to 0.25), more preferably 100: (0.12 to 0.20); high-nickel ternary positive electrode material base material and amorphous Al (aluminum) subjected to washing and drying ₂ O ₃ The mass ratio of (2) is 100: (0.08 to 0.25), preferably 100: (0.1 to 0.22), more preferably 100: (0.12-0.20).

In the third step, zrB ₂ Amorphous Al ₂ O ₃ The description is omitted here with reference to the relevant limitation in step one. And the limitation in the first step and the third step is independent limitation, namely ZrB in the first step and the third step ₂ Amorphous Al ₂ O ₃ May be different.

In the third step, a high-speed mixer or a mechanical fusion machine is usually used as the equipment for uniformly mixing, and a high-speed mixer is preferable.

In the third step, the oxygen concentration is preferably not less than 95%.

In the third step, the conditions for the secondary calcination are as follows: raising the temperature to 350-720 ℃ at a heating rate of 1-20 ℃/H, and preserving heat for 1-24H; preferably, the temperature is raised to 400-680 ℃ at a heating rate of 1-20 ℃/H, and the heat preservation time is 3-14H; more preferably, the temperature is raised to 420-580 ℃ at a heating rate of 1-20 ℃/H, and the heat preservation time is 6-11H.

In the fourth step, the high nickel ternary positive electrode material base material and LiPO are subjected to secondary calcination ₃ Preferably 100: (0.3-1.0); more preferably 100: (0.4-0.8).

In the fourth step, the conditions for three calcination are as follows: raising the temperature to 200-400 ℃ at a heating rate of 1-20 ℃/H, and preserving heat for 1-10H; preferably, the temperature is raised to 240-385 ℃ at a heating rate of 1-20 ℃/H, and the temperature is kept for 3-8 hours; more preferably, the temperature is raised to 300-380 ℃ at a heating rate of 1-20 ℃/H for 4-7H.

In the fourth step, the oxygen concentration is preferably not less than 95%.

In the fifth step, the low-temperature batch mixing and filling is carried out by adopting the heating rate of 1-5 ℃/min to 100-200 ℃, the combination of the tank body and the mould temperature is heated, the materials are mixed for 0.5-6 h according to the set temperature, and the exhaust replacement is carried out every 0.5h, so that the main purposes of removing the moisture on the surface of the particles and repairing the surface of the particles are achieved; and (5) vacuum packaging after completion. Preferably, the low-temperature batch mixing is heated to 120-180 ℃ at a heating rate of 1-4 ℃/min, mixed for 2.0-5.0 h, and replaced once every 0.5 h; preferably, the mixture is heated to 140-160 ℃ at a heating rate of 2-3 ℃/min and mixed for 3.0-4.0 h, and the replacement is carried out every 0.5 h.

In the fifth step, the crushing apparatus is usually a colloid mill, and the low-temperature batch mixing is usually performed in a batch mixing tank, and a drying gas (dehydrated and decarbonated gas) is introduced to protect the materials.

The terms used in the present invention generally have meanings commonly understood by those of ordinary skill in the art unless otherwise indicated. In order to better understand the technical solutions of the present invention, the following description will be given in detail with reference to examples.

In the following examples, various processes and methods, which are not described in detail, are conventional methods well known in the art. Materials, reagents, devices, instruments, equipment and the like used in the examples described below are commercially available unless otherwise specified.

The invention is further illustrated by the following examples.

Example 1

Step one, preparing a precursor Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (D50:3.9±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (2000g)、LiOH·H ₂ O(941.36g)、ZrB ₂ (5.4979g)、Al ₂ O ₃ (3.7867g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 860 ℃ for sintering for 11.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Washing the substrate obtained in the step II with water for 30s according to the water-to-material ratio of 1:1.5, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1500g and coating additive (ZrB) ₂ (2.2289g)、Al ₂ O ₃ (1.8176 g)) are put into a high-speed mixer according to three steps of 100rmp/2min, 1200rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 8.0h at 530 ℃ under oxygen or oxygen air (5:5) atmosphere, and the secondary calcined base material is obtained through cooling, crushing, sieving and demagnetizing.

Step four, sampling 1500g of the secondary calcined substrate obtained in the step three and coating additive LiPO ₃ (5.6262 g) putting the materials into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 6.0h at 350 ℃ under oxygen or oxygen-free (5:5) atmosphere, cooling, crushing, sieving and demagnetizing to obtain the three-time calcined base material.

And fifthly, under the condition of dehydration and decarbonization gas, the three-time calcined base material obtained in the step four is put into a batch mixing tank at 150 ℃ for mixing for 3 hours, and is discharged and packaged after the temperature is reduced to be less than or equal to 45 ℃ and relevant physicochemical data are tested.

Example 2

Step one, preparing a precursor Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (D50:10.5±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (2000g)、LiOH·H ₂ O(941.36g)、ZrB ₂ (5.4979g)、Al ₂ O ₃ (3.7867g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 840 ℃ for sintering for 11.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Washing the substrate obtained in the step II with water for 30s according to the water-to-material ratio of 1:1.5, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g of the substrate and coating additive (ZrB) ₂ (2.3775g)、Al ₂ O ₃ (1.8176 g)) are put into a high-speed mixer according to three steps of 100rmp/2min, 1200rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 8.0h at 480 ℃ under oxygen or oxygen air (5:5) atmosphere, and then are cooled, crushed, sieved and demagnetized to obtain the secondary calcined substrate.

Step four, sampling 1500g of the secondary calcined substrate obtained in the step three and coating additive LiPO ₃ (5.6262 g) is put into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 6.0h at 350 ℃ under oxygen or oxygen air (5:5) atmosphere, and the three times of calcination base materials are obtained after cooling, crushing, sieving and demagnetizing.

Example 3

Step one, preparing a precursor Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (D50:3.9±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (2000g)、LiOH·H ₂ O(941.36g)、ZrB ₂ (5.7478g)、Al ₂ O ₃ (4.5440g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 830 ℃ for sintering for 11.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Washing the substrate obtained in the step II with water for 30s according to the water-to-material ratio of 1:1.5, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g of the substrate and coating additive (ZrB) ₂ (2.3775g)、Al ₂ O ₃ (1.8176 g)) are put into a high-speed mixer according to three steps of 100rmp/2min, 1200rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 8.0h at 530 ℃ under oxygen or oxygen air (5:5) atmosphere, and the secondary calcined base material is obtained through cooling, crushing, sieving and demagnetizing.

Step four, sampling 1500g of the secondary calcined substrate obtained in the step three and coating additive LiPO ₃ (6.5639 g) is put into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 6.0h at 350 ℃ under oxygen or oxygen air (5:5) atmosphere, and the three times of calcination base materials are obtained after cooling, crushing, sieving and demagnetizing.

Example 4

Step one, preparing a precursor Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (D50:10.5±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (2000g)、LiOH·H ₂ O(941.07g)、ZrB ₂ (5.7478g)、Al ₂ O ₃ (4.5440g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 800 ℃ for sintering for 11.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Example 5

Step one, preparing a precursor Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (D50:3.5±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (2000g)、LiOH·H ₂ O(936.76g)、ZrB ₂ (6.2476g)、Al ₂ O ₃ (5.6801g)。

Step (a)3. Washing the substrate obtained in the second step with water according to a water-to-material ratio of 1:1.5 for 30s, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g and coating additive (ZrB) ₂ (2.3775g)、Al ₂ O ₃ (1.8176 g)) are put into a high-speed mixer according to three steps of 100rmp/2min, 1200rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 8.0h at 530 ℃ under oxygen or oxygen air (5:5) atmosphere, and the secondary calcined base material is obtained through cooling, crushing, sieving and demagnetizing.

Step four, sampling 1500g of the secondary calcined substrate obtained in the step three and coating additive LiPO ₃ (8.4393 g) is put into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 6.0h at 350 ℃ under oxygen or oxygen air (5:5) atmosphere, and the three times of calcination base materials are obtained after cooling, crushing, sieving and demagnetizing.

Example 6

Step one, preparing a precursor Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (D50:9.5±0.5μm)、LiOH·H ₂ O (D50:6+ -2 μm) and additives (ZrB) ₂ (δ+θ+α+γ=25% +30% +40% +5%) amorphous Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (2000g)、LiOH·H ₂ O(936.76g)、ZrB ₂ (6.2476g)、Al ₂ O ₃ (5.6801g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 760 ℃ for sintering for 11.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Step three, the base material obtained in the step two is mixed according to the water-material ratio1:1.5 water washing for 30s, vacuum filtration followed by drying and dewatering in a vacuum oven at 150 ℃ C./6 h, which samples 1600g with coating additive (ZrB) ₂ (2.3775g)、Al ₂ O ₃ (1.8176 g)) are put into a high-speed mixer according to three steps of 100rmp/2min, 1200rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 8.0h at 480 ℃ under oxygen or oxygen air (5:5) atmosphere, and then are cooled, crushed, sieved and demagnetized to obtain the secondary calcined substrate.

Comparative example 1

Step one, preparing a precursor Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (D50:3.9±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (2000g)、LiOH·H ₂ O(941.36g)、ZrO ₂ (5.9494g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (1.8158g)。

Step three, washing the base material obtained in the step two with water according to the water-material ratio of 1:1.5 for 30s,vacuum-filtered and dried in a vacuum oven at 150 ℃ C./6 h for dehydration, which samples 1600g with coating additive (ZrO ₂ (2.5961g)、B ₂ O ₃ (1.5613g)、γ-Al ₂ O ₃ (3.7867 g)); putting the materials into a high-speed mixer according to three-stage 100rmp/2min, 1200rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 8.0h at 530 ℃ under oxygen or oxygen-air (5:5) atmosphere, cooling, crushing, sieving and demagnetizing the sintered powders to obtain the secondary calcined substrate.

Comparative example 2

Step one, preparing a precursor Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (D50:10.5±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.83 Co _0.11 Mn _0.06 (OH) ₂ (2000g)、LiOH·H ₂ O(941.36g)、ZrO ₂ (5.9494g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (3.7867g)。

Step three, the base material obtained in the step two is processedWashing with water according to a water-to-material ratio of 1:1.5 for 30s, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, sampling 1600g and coating additive (ZrO ₂ (2.5961g)、B ₂ O ₃ (1.5613g)、γ-Al ₂ O ₃ (1.8158 g)); putting the materials into a high-speed mixer according to three-stage 100rmp/2min, 1200rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 8.0h at 480 ℃ under oxygen or oxygen-air (5:5) atmosphere, cooling, crushing, sieving and demagnetizing the sintered powders to obtain the secondary calcined substrate.

Comparative example 3

Step one, preparing a precursor Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (D50:3.9±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (2000g)、LiOH·H ₂ O(941.07g)、ZrO ₂ (6.2198g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (4.5395g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 815 ℃ for sintering for 12.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Step three,Washing the substrate obtained in the second step with water according to a water-to-material ratio of 1:1.5 for 30s, vacuum-filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g of the substrate and coating additive (ZrO ₂ (2.5961g)、B ₂ O ₃ (1.5613g)、γ-Al ₂ O ₃ (1.8158 g)); putting the materials into a high-speed mixer according to three-stage 100rmp/2min, 1200rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 8.0h at 530 ℃ under oxygen or oxygen-air (5:5) atmosphere, cooling, crushing, sieving and demagnetizing the sintered powders to obtain the secondary calcined substrate.

Step four, sampling 1500g of the substrate obtained in the step three and coating additive LiPO ₃ (6.5639 g) is put into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 6.0h at 350 ℃ under oxygen or oxygen air (5:5) atmosphere, and the three times of calcination base materials are obtained after cooling, crushing, sieving and demagnetizing.

Comparative example 4

Step one, preparing a precursor Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (D50:10.5±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.88 Co _0.07 Mn _0.05 (OH) ₂ (2000g)、LiOH·H ₂ O(941.07gg)、ZrO ₂ (6.2198g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (4.5395g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 800 ℃ for sintering for 12.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Washing the substrate obtained in the step II with water for 30s according to the water-material ratio of 1:1.5, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g of the substrate and coating additive (ZrO ₂ (2.5961g)、B ₂ O ₃ (1.5613g)、γ-Al ₂ O ₃ (1.8158 g)); putting the materials into a high-speed mixer according to three-stage 100rmp/2min, 1200rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 8.0h at 480 ℃ under oxygen or oxygen-air (5:5) atmosphere, cooling, crushing, sieving and demagnetizing the sintered powders to obtain the secondary calcined substrate.

Comparative example 5

Step one, preparing a precursor Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (D50:3.5±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (2000g)、LiOH·H ₂ O(936.76g)、ZrO ₂ (6.7606g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (5.6774g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 785 ℃ for sintering for 13.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

Washing the substrate obtained in the step II with water for 30s according to the water-material ratio of 1:1.5, vacuum-pumping filtering, drying and dehydrating in a vacuum oven at 150 ℃/6h, and sampling 1600g of the substrate and coating additive (ZrO ₂ (2.5961g)、B ₂ O ₃ (1.5613g)、γ-Al ₂ O ₃ (1.8158 g)); putting the materials into a high-speed mixer according to three-stage 100rmp/2min, 1200rpm/30min and 200rmp/3min, uniformly mixing the three powders, putting the mixed powders into a crucible, sintering the mixed powders for 8.0h at 530 ℃ under oxygen or oxygen-air (5:5) atmosphere, cooling, crushing, sieving and demagnetizing the sintered powders to obtain the secondary calcined substrate.

Step four, sampling 1500g of the secondary calcined substrate obtained in the step three and coating additive LiPO ₃ (8.4303 g) is put into a high-speed mixer according to three steps of 100rmp/2min, 1000rpm/30min and 200rmp/3min, three kinds of powder are evenly mixed and then are put into a crucible, sintered for 6.0h at 350 ℃ under oxygen or oxygen air (5:5) atmosphere, and the three times of calcination base materials are obtained after cooling, crushing, sieving and demagnetizing.

Comparative example 6

Step one, preparing a precursor Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (D50:9.5±0.5μm)、LiOH·H ₂ O (D50:6.+ -. 2 μm) and additives (ZrO ₂ 、B ₂ O ₃ 、γ-Al ₂ O ₃ ) Raw materials are respectively weighed Ni _0.94 Co _0.03 Mn _0.03 (OH) ₂ (2000g)、LiOH·H ₂ O(936.76g)、ZrO ₂ (6.7606g)、B ₂ O ₃ (3.2234g)、γ-Al ₂ O ₃ (5.6774g)。

Step two, transferring the materials into a high-speed mixer, uniformly mixing the three powders by adopting three sections of 200rmp/2min, 800rpm/20min and 100rmp/3min, loading the three powders into a crucible, transferring the crucible into a muffle furnace, heating the crucible to 460 ℃ at 3 ℃/min for sintering for 4.0h, heating the crucible to 710 ℃ for sintering for 4.0h, and heating the crucible to 760 ℃ for sintering for 13.0h; cooling, crushing, sieving and demagnetizing to obtain the base material.

The high nickel ternary cathode materials prepared in examples 1 to 6 and comparative examples 1 to 6 were analyzed for physicochemical indexes of samples using related equipment such as a scanning electron microscope, a laser particle size instrument, a Switzerland Universal automatic titration instrument, etc., which are well known to those skilled in the art, and the structures are shown in Table 1. SEM morphology features of the high nickel ternary cathode materials of examples 1-6 are shown in fig. 4.

Table 1 physicochemical indexes of the high-Nickel ternary cathode materials prepared in examples 1 to 6 and comparative examples 1 to 6

The high nickel ternary cathode materials prepared in examples 1 to 6 and comparative examples 1 to 6 were assembled into button cells using protocols for preparing cathode materials into lithium ion batteries well known to those skilled in the art; the blue electric test system is adopted, the first charge-discharge specific capacity and the 0.2C/0.5C/1.0C/2.0C rate discharge performance are shown in the table 2 under the condition of 25 ℃ and 0.1C in the voltage range of 3.0-4.3, and the cycle retention rate of the buckling electricity for 100 weeks is tested under the condition of 1C charge-discharge, and the results are shown in figures 1-3.

Table 2 properties of button cells assembled from the high nickel ternary cathode materials prepared in examples 1 to 6 and comparative examples 1 to 6

The soft package battery core prepared by the finished products obtained in the example 1 and the comparative example 1 is subjected to normal temperature and high temperature cycle performance evaluation, wherein the capacity of the soft package battery core is kept to be more than 96% under the condition of continuous normal temperature cycle 1800 ℃ under the condition of 1C/1C-100DOD (2.75V-4.20V), and the capacity of the soft package battery core is kept to be more than 92% under the condition of high temperature cycle 1200 ℃ as shown in figure 5; the DCIR increase was low as shown in table 3.

Table 3 cyclic DCIR test data for example 1 and comparative example 1

1-4 and tables 1-3 show that the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary positive electrode material prepared by the method has high structure and thermal stability, and has high gram specific capacity, low DCIR growth, long-cycle performance, high-temperature storage performance and other comprehensive excellent performances.

It is apparent that the above embodiments are merely examples for clarity of illustration and are not limiting examples. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary or exhaustive of all examples. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims

1. Boron zirconium compound and amorphous aluminum oxide modified high nickel ternary positive electrode material, which is characterized in thatThe chemical general formula of the high-nickel ternary positive electrode material is LiNi _x Co _y Mn _z B _a Zr _b Al _c PO ₂ Wherein x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.30,0, z is more than or equal to 0.30, and x+y+z+a+b+c=1.

2. The method for preparing the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary cathode material as claimed in claim 1, which is characterized by comprising the following steps:

the doped compound is ZrB ₂ Amorphous Al ₂ O ₃ ，ZrB ₂ Is in a hexagonal crystal form, the purity is more than or equal to 99 percent, and the amorphous Al ₂ O ₃ Is delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ One or more of the high nickel ternary precursors, li in lithium source ⁺ The molar ratio of the total doping elements in the doping compound is 1: (0.96-1.10): (0.0001-0.01), high nickel ternary precursor and ZrB ₂ The mass ratio of (2) is 100: (0.05-0.60), high nickel ternary precursor and amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.10 to 0.50);

3. The method for preparing the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary cathode material according to claim 2, wherein in the first step, the high-nickel ternary precursor is a small-particle high-nickel ternary precursor or a large-particle high-nickel ternary precursor, the particle size of the small-particle high-nickel ternary precursor is 2-6 μm, and the particle size of the large-particle high-nickel ternary precursor is 7-15 μm;

The high-nickel ternary precursor is a large-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 8-16 mu m, and the particle size of the prepared high-nickel ternary positive electrode material is 8-16 mu m;

the high-nickel ternary precursor is a small-particle high-nickel ternary precursor, the particle size of the prepared high-nickel ternary positive electrode material substrate is 2.5-6.0 mu m, and the particle size of the prepared high-nickel ternary positive electrode material is 2.5-6.0 mu m.

4. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary cathode material according to claim 2, wherein in the first step,

the lithium source is LiOH, liOH.H ₂ O、Li ₂ CO ₃ And LiNO ₃ The particle size of the lithium source is 4-10 μm.

5. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary positive electrode material according to claim 2, wherein in the first and third steps, delta-Al ₂ O ₃ 、θ-Al ₂ O ₃ 、α-Al ₂ O ₃ 、γ-Al ₂ O ₃ The mass ratio of (3) is respectively and independently (0-80): (0-80): (0-80): (0-10);

the ZrB ₂ Prepared by the following method: uniformly mixing zirconium metal, boron carbide and boron nitride, and heating and firing in an inert atmosphere to obtain the hexagonal crystal ZrB ₂ The block is decarburized, cooled and crushed to 1 to 15 mu m to obtain ZrB ₂ 。

6. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary cathode material according to claim 2, wherein in the first step,

the equipment adopted by the primary sintering is a muffle furnace or a tube furnace, and the primary sintering conditions are as follows: the temperature is raised to 400-460 ℃ for 3-5 h at a temperature raising rate of 2-4 ℃/min, the temperature is raised to 580-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage;

or, the equipment adopted by primary sintering is an atmosphere roller kiln or a rotary kiln, and the primary sintering conditions are as follows: the temperature is raised to 400-460 ℃ for 3-5 h at a temperature raising rate of 5-20 ℃/h, the temperature is raised to 580-740 ℃ for 3-4 h at the second stage, and the temperature is raised to 740-970 ℃ for 8-20 h at the third stage.

7. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary cathode material according to claim 2, wherein in the second step,

the conditions of water washing are as follows: the mass ratio of the material to the water is 1: (0.5-3.0), the time is 10-120 s, filter pressing and pre-dehydration are carried out in the water washing process, nitrogen is introduced into the filter after the pre-dehydration is finished to purge for 1-4H, and the water content of a filter cake is controlled to be less than or equal to 7%;

the drying temperature is 120-200 ℃ and the drying time is 1-12 h.

8. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary cathode material according to claim 2, wherein in the third step,

high nickel ternary positive electrode material substrate and ZrB (zinc-zinc) dried by water washing ₂ The mass ratio of (2) is 100: (0.05-0.30), washing and drying the high nickel ternary positive electrode material base material and the amorphous Al ₂ O ₃ The mass ratio of (2) is 100: (0.08-0.25);

the conditions for the secondary calcination are as follows: raising the temperature to 400-680 ℃ at the heating rate of 1-20 ℃/H, and preserving the heat for 3-14H.

9. The method for preparing a boron zirconium compound and amorphous aluminum oxide modified high nickel ternary cathode material according to claim 2, wherein in the fourth step,

secondary calcination high-nickel ternary positive electrode material substrate and LiPO ₃ The mass ratio of (2) is 100: (0.3-1.3);

the conditions for the three calcination are: raising the temperature to 240-385 ℃ at a heating rate of 1-20 ℃/H, and preserving the heat for 3-8H.

10. The method for preparing the boron zirconium compound and amorphous aluminum oxide modified high-nickel ternary cathode material according to claim 2, wherein in the fifth step, the conditions of low-temperature mixing are as follows: heating to 120-180 ℃ at a heating rate of 1-4 ℃/min, mixing for 2.0-5.0 h, and replacing every 0.5-1.0 h.