A multi-element coated ternary positive electrode material and a preparation method thereof

Abstract

The present application relates to the technical field of lithium ion battery cathode material, in particular to a kind of multi-element coated ternary cathode material and preparation method thereof.The present application provides a kind of multi-element coated ternary cathode material, the ternary cathode material includes lithium nickel cobalt manganese oxide ternary cathode material and the lithium niobium tungsten borate coating material attached to its surface, wherein the chemical composition general formula of the lithium niobium tungsten borate coating material is LiNb 1‑6x / 5‑3y / 5 W x B y O3, 0 The mass of the lithium niobium tungsten borate coating material is 0.02%~0.4% of the mass of the lithium nickel cobalt manganese oxide ternary cathode material.The coulomb efficiency of the ternary cathode material provided by the present application can reach 98.2%, the 100 cycle capacity retention rate can reach 88.4%, and the reversible capacity can reach 182mAh / g.Furthermore, the preparation process of the ternary cathode material is simple, the production cost is low, and it is suitable for mass production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery cathode material, and particularly relates to a multi-element coated ternary cathode material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of new energy industry, as a core component of lithium ion battery, the performance of cathode material directly affects the energy density, cycle life and safety of the battery, and also occupies an important position in the total cost of the battery. Among many cathode materials, high-nickel ternary material has become the most potential cathode material system to achieve high energy density and low cost target due to its low cobalt content and high reversible capacity. However, with the increase of nickel content, the material faces problems such as decline in surface structure stability and accelerated dissolution of transition metal ions, which not only leads to the attenuation of battery cycle performance and deterioration of high-temperature performance, but also brings significant safety hazards. In addition, during long-term cycling, side reactions continuously occur at the interface between the cathode material and the electrolyte, causing the destruction of the active material structure and the increase of the interface impedance, which seriously restricts the improvement of the overall electrochemical performance of the battery.

[0003] In view of the above problems, the main modification strategies for high-nickel ternary cathode material at present include element doping, surface coating and surface pretreatment. Among them, element doping can effectively broaden the insertion and de-insertion range of lithium ions, improve the material structure uniformity and electronic transmission path, reduce the pulverization of active material during charging and discharging, change the electronic structure of the material, reduce the lithium ion diffusion resistance, and significantly prolong the cycle life of the battery. The surface coating technology can effectively prevent the generation of gas during the charging and discharging process of the cathode material, avoid the risk of bulging or explosion, and isolate the active material from the electrolyte to reduce side reactions. More importantly, the synergistic effect of the coating layer and the material core can enhance the mechanical properties and thermal stability of the material, greatly prolonging the service life of the battery. Therefore, reasonable selection of doping / coating elements, optimization of material chemical structure and improvement of preparation process have become the key technical means to improve the performance of high-nickel ternary material. SUMMARY

[0004] Therefore, the present application provides a multi-element coated ternary cathode material and a preparation method thereof. The ternary cathode material realizes the improvement of the coated material through the synergistic effect of multiple elements, optimizes the surface structure of the layered oxide cathode material, reduces the interface impedance of the cathode material particles, and significantly improves the cycle performance and capacity retention rate of the lithium ion battery prepared by using the cathode material.

[0005] To solve the above technical problems, the present application provides a multi-element coated ternary positive electrode material, comprising a lithium nickel cobalt manganese oxide ternary positive electrode material and a lithium niobium tungsten borate coating material attached to the surface of the lithium nickel cobalt manganese oxide ternary positive electrode material, wherein the chemical composition of the lithium niobium tungsten borate coating material is LiNb 1-6x / 5-3y / 5 W x B y O3, 0 < x < 0.1, 0 < y < 0.1, 1-6x / 5-3y / 5 > 0; the mass of the lithium niobium tungsten borate coating material is 0.02% to 0.4% of the mass of the lithium nickel cobalt manganese oxide ternary positive electrode material.

[0006] The lithium niobium tungsten borate coating layer provided by the present application is a multi-element doped coating layer. On the basis of ensuring that the original structure of lithium niobate is not changed, tungsten and boron are additionally doped to replace part of the position of niobium elements, so that the original electronic conductivity of lithium niobate can be preserved, and the cycle stability and rate performance of the obtained battery can be improved. Therefore, the advantages of doping multiple elements in the coating material are utilized to jointly promote the effect of the obtained positive electrode material in lithium ion batteries.

[0007] In combination with the first aspect, the lithium niobium tungsten borate coating material completely or partially coats the lithium nickel cobalt manganese oxide ternary positive electrode material; wherein the partial coating includes regional coating and point coating.

[0008] In combination with the first aspect, the average particle size of the lithium niobium tungsten borate coating material is 30 to 500 nm.

[0009] Preferably, the average particle size of the lithium niobium tungsten borate coating material is 40 to 490 nm.

[0010] The average particle size of the lithium niobium tungsten borate coating material provided by the present application is not more than 500 nm at most, and the coating material can be more uniformly coated on the surface of the positive electrode material during the coating process.

[0011] In combination with the first aspect, in the multi-element coated ternary positive electrode material, the mass of the lithium niobium tungsten borate coating material is 0.02% to 0.4% of the mass of the lithium nickel cobalt manganese oxide ternary positive electrode material. This mass ratio can ensure that the obtained multi-element coated ternary positive electrode material has excellent comprehensive performance.

[0012] Preferably, the mass of the lithium niobium tungsten borate coating material is 0.02% to 0.15% of the mass of the lithium nickel cobalt manganese oxide ternary positive electrode material.

[0013] In combination with the first aspect, the chemical composition of the lithium niobium tungsten borate coating material is LiNb 1-6x / 5-3y / 5 W x B yO3, wherein 0.02≤x≤0.08, 0.02≤y≤0.08, 0.856≤1-6x / 5-3y / 5≤0.964.

[0014] Preferably, the chemical composition of the lithium niobium tungsten borate coating material is LiNb 1-6x / 5-3y / 5 W x B y O3, wherein 0.04≤x≤0.075, 0.04≤y≤0.06, 0.874≤1-6x / 5-3y / 5≤0.928.

[0015] Preferably, the chemical composition of the lithium niobium tungsten borate coating material is LiNb 1-6x / 5-3y / 5 W x B y O3, wherein 0.04≤x≤0.0725, 0.04≤y≤0.06, 0.877≤1-6x / 5-3y / 5≤0.928.

[0016] Further preferably, the chemical composition of the lithium niobium tungsten borate coating material is LiNb 0.877 W 0.0725 B 0.06 O3.

[0017] The second aspect of the present application provides a preparation method of the above-mentioned multi-element coated ternary positive electrode material, and the steps include:

[0018] Preparation of uncoated ternary positive electrode material: uniformly mix lithium source and nickel-cobalt-manganese hydroxide precursor in proportion, and sequentially perform pre-calcination and high-temperature calcination under oxygen atmosphere to obtain the lithium nickel cobalt manganese oxide ternary positive electrode material; preparation of coating material: uniformly mix lithium source, niobium source, tungsten source and boron source in proportion, and perform sintering and refinement treatment to obtain the lithium niobium tungsten borate coating material; uniformly mix the lithium nickel cobalt manganese oxide ternary positive electrode material and the lithium niobium tungsten borate coating material in proportion, and calcine at 550-650℃ for 6-8h to obtain the multi-element coated ternary positive electrode material.

[0019] The preparation method of the multi-element coated ternary positive electrode material provided by the present application has simple steps and is easy to operate, only needs to uniformly mix lithium source, niobium source, tungsten source and boron source in proportion, and perform sintering and refinement treatment to obtain the lithium niobium tungsten borate coating material; and then uniformly mix the lithium nickel cobalt manganese oxide ternary positive electrode material and the coating material, and calcine at a certain temperature to obtain the multi-element coated ternary positive electrode material.

[0020] In combination with the second aspect, the lithium source is selected from at least one of lithium hydroxide, lithium oxide, lithium nitrate, lithium acetate, lithium oxalate, lithium citrate and lithium carbonate; the niobium source is selected from at least one of niobium oxide and niobium hydroxide; the tungsten source is selected from at least one of tungsten oxide and tungstic acid; and the boron source is selected from at least one of boron oxide and boric acid.

[0021] Preferably, when preparing lithium niobium tungsten borate coated material, the molar amount of the added lithium source (calculated as lithium ions) is 5% to 10% excess of its theoretical molar amount.

[0022] Preferably, the general chemical formula of the nickel-cobalt-manganese hydroxide precursor is Ni x Co y Mn 1-x-y (OH)2, where 0.6≤x<1, 0<y<1, 1-xy>0, x+y+z=1.

[0023] In conjunction with the second aspect, the pre-calcination is calcination at 550~650℃ for 4~6 hours, the high-temperature calcination is calcination at 880~920℃ for 8~12 hours, and the sintering is sintering at 650~750℃ for 4~6 hours.

[0024] Preferably, the refining process includes: coarsely crushing the sintered sample through a nail disc mill to obtain a primary particle size precursor; sand milling the primary particle size precursor to obtain a secondary particle size precursor; and drying and air-jet crushing the secondary particle size precursor to obtain a lithium niobium tungsten borate coated material.

[0025] Preferably, the grinding media size in the sand milling step is 0.1~0.5mm, and the grinding media material is at least one of alumina or zirconium oxide.

[0026] Preferably, the grinding step involves a rotation speed of 800-1000 rpm, a grinding time of 3-6 hours, and a solid content of 25-40%.

[0027] Preferably, the secondary particle size precursor is microwave dried for 15-30 minutes and the microwave power is 2000-2400W.

[0028] Preferably, the pressure of the airflow agitation is 0.6~0.8MPa, and the frequency of the stager wheel is 120~190Hz.

[0029] Preferably, when mixing the raw materials, a mixer can be used, with the mixer speed set to 1000~2000 rpm, and preferably mixed 3~5 times, each time for 10~20 minutes.

[0030] A third aspect of the present invention provides a lithium-ion battery comprising the above-described ternary cathode material coated with multiple elements or the ternary cathode material coated with multiple elements prepared by the above-described preparation method.

[0031] The beneficial effects of this invention are as follows: By utilizing a doping-modified coating layer method, this invention significantly improves the structural stability and electrochemical performance of the obtained ternary cathode material. Simultaneously, this ternary cathode material exhibits outstanding safety performance and long service life in lithium-ion battery applications. Through specific doping modifications to the coating material, this invention obtains a multi-element coated ternary cathode material with lower interfacial impedance and longer cycle life. The coulombic efficiency of this cathode material can reach 98.2%, the capacity retention rate after 100 cycles can reach 88.4%, and the reversible capacity can reach 182 mAh / g. Furthermore, the preparation process of the multi-element coated ternary cathode material provided by this invention is simple and the production cost is low, making it suitable for mass production. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a scanning electron microscope image of the lithium niobium tungsten borate-coated material obtained in Example 1 of the present invention;

[0034] Figure 2 This is a scanning electron microscope image of the lithium niobium tungsten borate-coated material obtained in Example 2 of the present invention;

[0035] Figure 3 This is a scanning electron microscope image of the lithium niobium tungsten borate coated material obtained in Example 3 of the present invention;

[0036] Figure 4 This is a scanning electron microscope image of the lithium niobium tungsten borate-coated material obtained in Example 4 of the present invention;

[0037] Figure 5 This is a scanning electron microscope image of the lithium niobium tungsten borate-coated material obtained in Example 5 of the present invention;

[0038] Figure 6 This is a scanning electron microscope image of the lithium niobium tungsten borate coated material obtained in Example 6 of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0041] Modification strategies for high-nickel ternary cathode materials mainly include element doping, surface coating, and surface pretreatment. Element doping effectively broadens lithium-ion transport channels, improves material structural stability, optimizes the electron conduction network, and suppresses particle pulverization during charging and discharging. Simultaneously, by regulating the material's electronic structure, it lowers the lithium-ion diffusion barrier, thus significantly improving battery cycle stability. Surface coating technology constructs a protective layer on the surface of the active material. This not only prevents direct contact between the material and the electrolyte, reducing side reactions, but also suppresses gas generation during charging and discharging, improving battery safety. More importantly, the synergistic effect between the coating layer and the material core enhances the material's mechanical properties and thermal stability, significantly extending battery life. Therefore, the rational selection of doping / coating elements, optimization of the material's chemical structure, and improvement of the preparation process have become key technical pathways for improving the performance of high-nickel ternary materials. However, there is still considerable room for improvement in the cycle performance and capacity retention of existing high-nickel ternary cathode materials modified by element doping, surface coating, or a combination thereof.

[0042] In view of this, the present invention provides a ternary cathode material with multi-element coating and its preparation method. The ternary cathode material improves the coating layer through the synergistic effect of multiple elements, optimizes the surface structure of the layered oxide cathode material, reduces the interfacial impedance of the cathode material particles, and significantly improves the cycle performance and capacity retention of lithium-ion batteries made with the cathode material.

[0043] The preparation method provided by the present invention will be described below through specific embodiments.

[0044] Unless otherwise specified, all raw materials, reagents, and equipment used in this invention are conventional commercially available reagents and equipment. In the following examples and comparative examples, the nickel-cobalt-manganese hydroxide precursor used to prepare the ternary cathode material of lithium nickel cobalt-manganese oxide has a chemical composition of Ni. x Co y Mn 1-x-y(OH)₂, where 0.6 ≤ x < 1, 0 < y < 1, 1 - xy > 0, and x + y + z = 1. When using a mixer, set the mixer speed to 1000~2000 rpm, mix 3~5 times, and mix for 10~20 minutes each time. Furthermore, when performing sand milling, use alumina or zirconium oxide as the abrasive material, with a grinding media size of 0.1~0.5 mm.

[0045] Example 1

[0046] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.964 W 0.02 B 0.02 O3.

[0047] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0048] Lithium hydroxide and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 650℃ for 4 hours in an oxygen atmosphere, and then heated to 920℃ for 8 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0049] Lithium hydroxide, niobium oxide, tungsten oxide, and boron oxide were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.964:0.02:0.02. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 650℃ for 6 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (25% solid content). This slurry was then processed by a sand mill at 800 rpm for 6 hours. The slurry was then microwave-dried (30 minutes at 2000 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill with an air jet crushing pressure of 0.8 MPa and a classifying wheel frequency of 140 Hz to obtain lithium niobium tungsten borate multi-component nanomaterials with small particle size and good dispersibility, i.e., lithium niobium tungsten borate coated material.

[0050] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 650°C for 6 hours to obtain the ternary cathode material with multi-element coating.

[0051] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below. Figure 1 As shown in the figure. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 490 nm, and the specific surface area is 13 m². 2 / g.

[0052] Example 2

[0053] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.928 W 0.04 B 0.04 O3.

[0054] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0055] Lithium nitrate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 630℃ for 4 hours in an oxygen atmosphere, and then heated to 910℃ for 9 hours to obtain lithium cobalt manganese oxide ternary cathode material.

[0056] Lithium oxide, niobium hydroxide, tungsten oxide, and boron oxide were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.928:0.04:0.04. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 630℃ for 6 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (30% solid content). This slurry was then processed by a sand mill at 850 rpm for 6 hours. The slurry was then microwave-dried (drying time 25 minutes, microwave frequency 2100 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.8 MPa and a classifying wheel frequency of 150 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated materials.

[0057] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 630°C for 6 hours to obtain the ternary cathode material with multi-element coating.

[0058] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below.Figure 2 As shown in the figure. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 280 nm, and the specific surface area is 21 m². 2 / g.

[0059] Example 3

[0060] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.892 W 0.06 B 0.06 O3.

[0061] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0062] Lithium oxalate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 600℃ for 5 hours in an oxygen atmosphere, and then calcined at 900℃ for 10 hours to obtain lithium cobalt manganese oxide ternary cathode material.

[0063] Lithium oxalate, niobium hydroxide, tungstic acid, and boron oxide were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.892:0.06:0.06. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 610℃ for 7 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (35% solid content). This slurry was then processed by a sand mill at 900 rpm for 5 hours. The slurry was then microwave-dried (drying time 25 minutes, microwave frequency 2300 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.7 MPa and a classifier wheel frequency of 160 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated materials.

[0064] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 610℃ for 7 hours to obtain the ternary cathode material with multi-element coating.

[0065] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below. Figure 3As shown. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 90 nm, and the specific surface area is 46 m². 2 / g.

[0066] Example 4

[0067] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.856 W 0.08 B 0.08 O3.

[0068] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0069] Lithium acetate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 580℃ for 5 hours in an oxygen atmosphere, and then calcined at 890℃ for 11 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0070] Lithium acetate, niobium hydroxide, tungsten oxide, and boron oxide were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.856:0.08:0.08. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 580℃ for 11 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 40%). This slurry was then processed by a sand mill at 930 rpm for 5 hours. The slurry was then microwave-dried (drying time 20 minutes, microwave frequency 2200 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.7 MPa and a classifier wheel frequency of 170 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated materials.

[0071] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 580°C for 7 hours to obtain the ternary cathode material with multi-element coating.

[0072] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below. Figure 4As shown in the figure. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 120 nm, and the specific surface area is 38 m². 2 / g.

[0073] Example 5

[0074] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.874 W 0.075 B 0.06 O3.

[0075] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0076] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 570℃ for 6 hours in an oxygen atmosphere, and then calcined at 880℃ for 12 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0077] Lithium citrate, niobium oxide, tungstic acid, and boric acid were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.874:0.075:0.06. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 570℃ for 8 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 28%). This slurry was then processed by a sand mill at 950 rpm for 4 hours. The slurry was then microwave-dried (drying time 20 minutes, microwave frequency 2300 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.6 MPa and a classifying wheel frequency of 180 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated material.

[0078] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 560°C for 8 hours to obtain the ternary cathode material with multi-element coating.

[0079] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below. Figure 5As shown in the figure. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 70 nm, and the specific surface area is 51 m². 2 / g.

[0080] Example 6

[0081] This embodiment provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.877 W 0.0725 B 0.06 O3.

[0082] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0083] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 560℃ for 6 hours in an oxygen atmosphere, and then calcined at 880℃ for 12 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0084] Lithium oxalate, niobium oxide, tungstic acid, and boric acid were weighed and proportioned according to a Li:Nb:W:B molar ratio of 1.05:0.877:0.0725:0.06. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 560℃ for 8 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 40%). This slurry was then processed by a sand mill at 1000 rpm for 3 hours. The slurry was then microwave-dried (drying time 15 minutes, microwave frequency 2400 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.6 MPa and a classifying wheel frequency of 190 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated materials.

[0085] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 550°C for 8 hours to obtain the ternary cathode material with multi-element coating.

[0086] The morphology of the obtained lithium niobium tungsten borate-coated material was analyzed using scanning electron microscopy (SEM). The SEM images are shown below. Figure 6As shown in the figure. Calculations show that the average particle size of the lithium niobium tungsten borate coated material is 40 nm, and the specific surface area is 57 m². 2 / g.

[0087] Comparative Example 1

[0088] This comparative example provides an uncoated lithium nickel cobalt manganese oxide ternary cathode material with the composition LiNi 0.6 Co 0.1 Mn 0.3 O2 is prepared according to the following steps:

[0089] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 570℃ for 6 hours in an oxygen atmosphere, and then calcined at 880℃ for 12 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0090] Comparative Example 2

[0091] This comparative example provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the lithium niobate coating is composed of LiNbO3.

[0092] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0093] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 590℃ for 5 hours in an oxygen atmosphere, and then calcined at 900℃ for 10 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0094] Lithium oxalate and niobium oxide were weighed and proportioned according to a Li:Nb molar ratio of 1.05:1. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 570℃ for 8 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 40%). This slurry was then processed by a sand mill at a speed of 970 rpm for 3 hours. The slurry was then microwave-dried (drying time 20 minutes, microwave frequency 2300 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.6 MPa and a classifying wheel frequency of 190 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated material.

[0095] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 570°C for 8 hours to obtain the ternary cathode material with multi-element coating.

[0096] Comparative Example 3

[0097] This comparative example provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium tungstate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium tungstate coating is Li2WO4.

[0098] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0099] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 610℃ for 5 hours in an oxygen atmosphere, and then calcined at 910℃ for 9 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0100] Lithium oxalate and tungstic acid were weighed and mixed in a Li:W molar ratio of 2.1:1. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 590℃ for 7 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 40%). This slurry was then processed by a sand mill at a speed of 920 rpm for 5 hours. The slurry was then microwave-dried (drying time 25 minutes, microwave frequency 2200 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.7 MPa and a classifying wheel frequency of 180 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated material.

[0101] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then calcined in a kiln at 620°C for 7 hours to obtain the ternary cathode material with multi-element coating.

[0102] Comparative Example 4

[0103] This comparative example provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the lithium borate coating is composed of Li3BO3.

[0104] The ternary cathode material with multi-component coating was prepared according to the following steps:

[0105] Lithium carbonate and nickel cobalt manganese hydroxide precursors were weighed and proportioned according to a Li:Ni:Co:Mn molar ratio of 1.05:0.6:0.1:0.3. The raw materials were mixed evenly using a mixer. The mixture was placed in a kiln and calcined at 620℃ for 4 hours in an oxygen atmosphere, and then calcined at 920℃ for 8 hours to obtain lithium nickel cobalt manganese oxide ternary cathode material.

[0106] Lithium oxalate and boron oxide were weighed and proportioned according to a Li:B molar ratio of 3.15:1. The raw materials were mixed evenly using a mixer, and the resulting mixture was sintered at 620℃ for 6 hours. The resulting lithium niobium tungsten borate was then pulverized using a disc mill, and water was added to form a slurry (solid content 40%). This slurry was then processed by a sand mill at 880 rpm for 6 hours. The slurry was then microwave-dried (drying time 30 minutes, microwave frequency 2000 MHz) and pulverized again using a disc mill. Finally, the pulverized material was processed using a three-dimensional air jet mill, with an air jet crushing pressure of 0.8 MPa and a classifying wheel frequency of 170 Hz, to obtain lithium niobium tungsten borate multi-element nanomaterials with small particle size and good dispersibility, namely lithium niobium tungsten borate coated material.

[0107] The ternary cathode material of lithium nickel cobalt manganese oxide and the coating material of lithium niobium tungsten borate were mixed evenly in a mixer. The amount of coating material added was 0.15% of the cathode material. The mixture was then placed in a kiln and calcined at 640°C for 6 hours to obtain the ternary cathode material with multi-element coating.

[0108] Comparative Example 5

[0109] This comparative example provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.982 W 0.01 B 0.01 O3.

[0110] The preparation method of this multi-element coated ternary cathode material is similar to that of Example 6, except that the molar ratio of Li:Nb:W:B is 1.05:0.982:0.01:0.01 when preparing the lithium niobium tungsten borate coating. All other steps and conditions are the same as in Example 6.

[0111] Comparative Example 6

[0112] This comparative example provides a ternary cathode material with multi-component coating, comprising a lithium nickel cobalt manganese oxide ternary cathode material and a lithium niobium tungsten borate coating layer attached to its surface, wherein the lithium nickel cobalt manganese oxide ternary cathode material is composed of LiNi 0.6 Co 0.1 Mn 0.3 O2, the composition of the lithium niobium tungsten borate coating is LiNb 0.838 W 0.09 B 0.09 O3.

[0113] The preparation method of this multi-element coated ternary cathode material is similar to that of Example 6, except that the molar ratio of Li:Nb:W:B is 1.05:0.838:0.09:0.09 when preparing the lithium niobium tungsten borate coating. All other steps and conditions are the same as in Example 6.

[0114] Test Example

[0115] To investigate the electrochemical performance and stability of the ternary cathode materials obtained in the above examples and comparative examples, the cathode materials prepared in Examples 1-6 and Comparative Examples 1-6 were assembled into lithium-ion batteries to examine their practical application effects. The battery assembly process is as follows: Carbon black conductive agent Super P (5%), binder PVDF (5%), oxalic acid (0.8%), and N-methylpyrrolidone were added to the obtained ternary cathode materials and stirred thoroughly. After coating and rolling, a cathode sheet with a thickness of 0.05-0.1 mm was prepared. Following the steps of: cathode sheet → 2 μL electrolyte → separator → 2 μL electrolyte → negative lithium sheet, the batteries were pressed into a coin cell under a certain pressure (10-40 MPa) to form a lithium-ion battery. Depending on the modified cathode material selected during preparation, the assembled batteries were respectively designated as lithium-ion batteries (Examples 1-6) and lithium-ion battery pairs (Comparative Examples 1-6).

[0116] The reversible capacity, coulombic efficiency, and capacity retention after 100 cycles of the assembled lithium-ion battery were determined using the AC impedance method and the constant current charge-discharge test method. The test conditions for coulombic efficiency, reversible capacity, and capacity retention after 100 cycles were: 1.0 C, 3.0–4.5 V, 100 cycles at room temperature (25°C). The specific test results are shown in Table 1.

[0117] Table 1

[0118]

[0119] The data in Table 1 show that, comparing Comparative Examples 2-4 with Comparative Example 1, when the ternary high-nickel cathode material is coated with lithium niobate, lithium tungstate, and lithium borate, the reversible capacity, coulombic efficiency, and 100-cycle capacity retention of the resulting lithium battery are all improved. This confirms that the lithium niobate, lithium tungstate, and lithium borate coatings have a positive effect on the performance development of cathode materials, and the lithium niobate coating has a better effect on the cathode material than the lithium tungstate and lithium borate coatings. Comparing the data from Comparative Examples 2-4 with Example 6, it is evident that, to further improve the structural stability and cycle retention of the ternary cathode material, when a coating containing niobium, tungsten, and boron is prepared using a doping method, the overall performance of the resulting lithium-ion battery is further improved, with a maximum coulombic efficiency of 98.2%, a maximum 100-cycle capacity retention of 88.4%, and a maximum reversible capacity of 182 mAh / g. Comparing Comparative Examples 5-6 and Example 6, it can be seen that the doping amount of niobium, tungsten and boron in the lithium niobium tungsten borate coating material provided by the present invention can achieve the best overall performance of lithium batteries. This may be closely related to the fact that the coating layer obtained by this doping amount can stabilize the structure of the cathode material, reduce agglomeration and isolate the electrolyte.

[0120] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A ternary cathode material with multi-element coating, characterized in that, This includes a ternary cathode material of lithium nickel cobalt manganese oxide and a coating material of lithium niobium tungsten borate attached to its surface, wherein the general chemical formula of the lithium niobium tungsten borate coating material is LiNb. 1-6x / 5-3y / 5 W x B y O3, 0 < x < 0.1, 0 < y < 0.1, 1 - 6x / 5 - 3y / 5 > 0; the mass of the lithium niobium tungsten borate coating material is 0.02% to 0.4% of the mass of the lithium nickel cobalt manganese ternary cathode material.

2. The ternary cathode material with multi-element coating as described in claim 1, characterized in that, The lithium niobium tungsten borate coating material completely or partially coats the lithium nickel cobalt manganese ternary cathode material; wherein, the partial coating includes regional coating and site coating.

3. The ternary cathode material with multi-element coating as described in any one of claims 1 to 2, characterized in that, The average particle size of the lithium niobium tungsten borate coated material is 30~500 nm.

4. The ternary cathode material with multi-element coating as described in any one of claims 1 to 2, characterized in that, The general chemical formula of the lithium niobium tungsten borate coating material is LiNb. 1-6x / 5-3y / 5 W x B y O3, where 0.02≤x≤0.08, 0.02≤y≤0.08, 0.856≤1-6x / 5-3y / 5≤0.

964.

5. The method for preparing the ternary cathode material with multi-element coating according to any one of claims 1 to 4, characterized in that the step include: Preparation of uncoated ternary cathode material: Lithium source and nickel cobalt manganese hydroxide precursor are mixed evenly in proportion, and pre-calcined and high-temperature calcined in oxygen atmosphere to obtain the lithium nickel cobalt manganese oxide ternary cathode material. Preparation of coating material: Lithium source, niobium source, tungsten source and boron source are mixed evenly in proportion, and then sintered and refined to obtain the lithium niobium tungsten borate coating material; The lithium nickel cobalt manganese oxide ternary cathode material and the lithium niobium tungsten borate coating material are mixed evenly in a certain proportion and calcined at 550~650℃ for 6~8h to obtain the multi-element coated ternary cathode material.

6. The method for preparing the ternary cathode material with multi-element coating as described in claim 5, characterized in that, The lithium source is selected from at least one of lithium hydroxide, lithium oxide, lithium nitrate, lithium acetate, lithium oxalate, lithium citrate, and lithium carbonate; the niobium source is selected from at least one of niobium oxide and niobium hydroxide; the tungsten source is selected from at least one of tungsten oxide and tungstic acid; and the boron source is selected from at least one of boron oxide and boric acid.

7. The method for preparing the ternary cathode material with multi-element coating as described in claim 5, characterized in that, The pre-calcination is carried out at 550~650℃ for 4~6 hours, the high-temperature calcination is carried out at 880~920℃ for 8~12 hours, and the sintering is carried out at 650~750℃ for 4~6 hours.

8. The method for preparing the ternary cathode material with multi-element coating as described in claim 5, characterized in that, The refining process includes: coarsely crushing the sintered sample through a nail disc mill to obtain a primary particle size precursor; sand milling the primary particle size precursor to obtain a secondary particle size precursor; and drying and air-jet crushing the secondary particle size precursor to obtain the lithium niobium tungsten borate coated material.

9. The method for preparing the ternary cathode material with multi-element coating as described in claim 8, characterized in that, The grinding media size in the sand milling step is 0.1~0.5mm, and the grinding media material is at least one of alumina or zirconium oxide; the grinding speed in the sand milling step is 800~1000 rpm, the sand milling time is 3~6h, and the solid content is 25~40%.

10. A lithium-ion battery, characterized in that, The lithium-ion battery comprises a ternary cathode material with multi-element coating as described in any one of claims 1 to 4, or a ternary cathode material with multi-element coating prepared according to the preparation method described in any one of claims 5 to 9.

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