阅读说明：本技术 一种金属硼化物与硼酸盐复合包覆改性的镍钴锰三元材料前驱体及其制备方法 (Metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor and preparation method thereof ) 是由 张宝 邓鹏� 程诚 林可博 周亚楠 邓梦轩 于 2021-07-20 设计创作，主要内容包括：本发明公开了一种金属硼化物与硼酸盐复合包覆改性的镍钴锰三元材料前驱体,包括镍钴锰三元材料前驱体其表面的金属硼化物与硼酸盐的复合物包覆层。还提供了一种改性三元前驱体的制备方法。本发明通过对镍钴锰三元前驱体表面包覆金属硼化物与硼酸盐复合物包覆层,两者复合的包覆层形成了结构稳定性和热稳定性好且电压平台稳定的包覆层,并能够提供锂离子和电子导电,提升了材料的导电性,复合包覆全面改善了材料的结构和性能,有利于提升镍钴锰三元材料的结构稳定性、循环性能和倍率性能。本发明的前驱体制备方法成本低,易实现、简单有效,且能制备所需结构、组成和性能的改性前驱体。(The invention discloses a nickel-cobalt-manganese ternary material precursor modified by compounding a metal boride and a borate, which comprises a compound coating layer of the metal boride and the borate on the surface of the nickel-cobalt-manganese ternary material precursor. Also provides a preparation method of the modified ternary precursor. According to the invention, the surface of the nickel-cobalt-manganese ternary precursor is coated with the metal boride and borate compound coating layer, the coating layer compounded by the metal boride and the borate compound forms a coating layer with good structural stability and thermal stability and stable voltage platform, lithium ion and electron conduction can be provided, the conductivity of the material is improved, the structure and performance of the material are comprehensively improved by compound coating, and the structural stability, the cycle performance and the rate capability of the nickel-cobalt-manganese ternary material are favorably improved. The precursor preparation method disclosed by the invention is low in cost, easy to implement, simple and effective, and can be used for preparing modified precursors with required structures, compositions and properties.)

1. The nickel-cobalt-manganese ternary material precursor is characterized by comprising a nickel-cobalt-manganese ternary material precursor and a coating layer located on the surface of the nickel-cobalt-manganese ternary material precursor, wherein the coating layer is a compound of a metal boride and a borate.

2. The metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor of claim 1, wherein the coating amount of the composite is 3-15% of the mass of the nickel-cobalt-manganese ternary material precursor; the thickness of the coating layer is 10-50 nm.

3. The metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor of claim 1 or 2, wherein the molecular formula of the nickel-cobalt-manganese ternary material precursor is Ni_1-x-yCo_xMn_y(OH)₂Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.1 and less than or equal to 0.3; the metal boride and the borate are compounded into Me_zB/Me₃(BO₃)₂Wherein z is more than or equal to 1.5 and less than or equal to 3, and Me is one or more than two of Mn, Co and Ni.

4. A preparation method of a metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor is characterized by comprising the following steps:

(1) preparing a nickel-cobalt-manganese ternary material precursor;

(2) dispersing a nickel-cobalt-manganese ternary material precursor in a solvent, adding a divalent metal salt and sodium borohydride in a protective atmosphere, stirring for reaction, after the reaction is finished, carrying out solid-liquid separation and drying, mixing with boric acid, grinding uniformly, and calcining to obtain the nickel-cobalt-manganese ternary material precursor coated by a metal boride and a borate in a composite manner.

5. The method for preparing the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor according to claim 4, wherein in the step (2), the molar ratio of the sodium borohydride to the boric acid to the divalent metal salt is 1-5: 10-20; the molar ratio of the divalent metal salt to the nickel-cobalt-manganese ternary material precursor is 1: 150-1: 40.

6. The method for preparing the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor according to claim 4, wherein in the step (2), the calcination temperature is 300-600 ℃, and the calcination time is 2-10 h.

7. The method for preparing the nickel-cobalt-manganese ternary material precursor compositely coated and modified by the metal boride and the borate according to claim 4, wherein in the step (2), the divalent metal salt is one or more of nitrate, acetate and sulfate of nickel, cobalt and manganese;

the solvent is ethanol, methanol and water.

8. The method for preparing the nickel-cobalt-manganese ternary material precursor compositely coated and modified by the metal boride and the borate according to any one of claims 4 to 7, wherein in the step (1), the method for preparing the nickel-cobalt-manganese ternary material precursor comprises the following steps: preparing a metal salt solution A of nickel, cobalt and manganese, adding the solution A into a reaction kettle at the speed of 5-10 mL/min, adding a sodium hydroxide solution and an ammonia water solution, controlling the pH value in the kettle to be 10.5-12, reacting for a certain time, filtering and drying to obtain a ternary material precursor Ni_1-x-yCo_xMn_y(OH)₂。

9. The method for preparing the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor according to claim 8, wherein the total molar concentration of nickel, cobalt and manganese elements in the solution A is 1-5 mol/L; the molar concentration of the sodium hydroxide solution is 1-5 mol/L; the molar concentration of the ammonia water is 5-12 mol/L.

10. The method for preparing the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor according to claim 8, wherein the reaction time is 10-50 h; the reaction temperature is 40-80 ℃.

Technical Field

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a nickel-cobalt-manganese ternary material precursor modified by composite coating of metal boride and borate and a preparation method thereof.

Background

The lithium ion battery is widely applied to daily life of people as the secondary power source with the most potential at present. At present, ternary materials in lithium ion battery materials are most widely applied due to high energy density and high stability. Ternary materials, particularly high nickel materials, are prone to cation mixing and discharging, so that the electrochemical performance of the materials is degraded. Therefore, the ternary precursor is subjected to modification treatment to stabilize the precursor structure so as to weaken Li⁺/Ni²⁺And cation mixing and discharging are carried out, so that the overall performance of the ternary material is improved.

The modification method mainly comprises the measures of surface coating, doping modification, structure optimization and the like, wherein the surface coating is used as the most extensive modification method, and the surface structure of the main material can be protected and optimized on the basis of not changing the structural performance of the main material, so that the electrochemical performance of the material is effectively improved. The single surface coating method, however, does not provide an overall performance improvement to the material due to its single protective efficacy. Therefore, the composite coating of the metal boride and the borate effectively improves the ion transfer rate of the material, and simultaneously improves the structural stability and the thermal stability of the material, so that an effective reference is provided for the practical application of the material in the future.

Disclosure of Invention

Aiming at the problems in the prior art, the ternary material precursor modified by the composite coating of the metal boride and the borate and the preparation method thereof are provided.

The purpose of the invention is realized by the following technical scheme:

the nickel-cobalt-manganese ternary material precursor comprises a nickel-cobalt-manganese ternary material precursor and a coating layer positioned on the surface of the nickel-cobalt-manganese ternary material precursor, wherein the coating layer is a compound of a metal boride and a borate.

Preferably, the coating amount of the composite is 3-15% of that of the nickel-cobalt-manganese ternary material precursor, more preferably 5-10%, and the thickness of the coating layer is 10-50 nm.

Preferably, the molecular formula of the nickel-cobalt-manganese ternary material precursor is Ni_1-x-yCo_xMn_y(OH)₂Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.1 and less than or equal to 0.3; the metal boride and the borate are compounded into Me_zB/Me₃(BO₃)₂Wherein z is more than or equal to 1.5 and less than or equal to 3, wherein Me is one or more than two of Mn, Co and Ni, and Me is preferably Ni.

As a general inventive concept, the invention also provides a preparation method of the metal boride and borate composite coating modified ternary material precursor, which comprises the following steps:

(1) preparing a metal salt solution A of nickel, cobalt and manganese according to the molar ratio of nickel, cobalt and manganese in a nickel-cobalt-manganese ternary material precursor; then adding the metal salt solution A into a reaction kettle at a certain speed, controlling the adding amount of a sodium hydroxide solution and an ammonia water solution, controlling the pH in the kettle to be 10.5-12, reacting for a certain time, filtering and drying to obtain a ternary material precursor Ni_{1-x- y}Co_xMn_y(OH)₂；

(2) Dispersing a nickel-cobalt-manganese ternary material precursor in a solvent, sequentially adding divalent metal salt and sodium borohydride in a protective atmosphere, stirring for reaction, after the reaction is finished, carrying out solid-liquid separation and drying, mixing the obtained product with a small amount of boric acid, uniformly grinding, and calcining to obtain the nickel-cobalt-manganese ternary material precursor coated by a metal boride and a borate in a composite manner.

Preferably, in the step (1), the certain speed is 5-10 mL/min, so that particles with required sizes can be obtained, uniform reaction can be ensured, and the obtained material particles are distributed uniformly.

Preferably, in the step (1), the nickel-cobalt-manganese ternary material precursor is nickel-cobalt-manganese hydroxide, and the molecular formula of the nickel-cobalt-manganese hydroxide is Ni_1-x-yCo_xMn_y(OH)₂Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.1 and less than or equal to 0.3.

Preferably, in the step (1), the divalent metal salt is one or more of a nitrate, an acetate and a sulfate of a divalent metal.

Preferably, in the step (1), the total molar concentration of nickel, cobalt and manganese in the metal salt solution A is 1-5 mol/L, and more preferably 2-3 mol/L.

Preferably, in the step (1), the molar concentration of the sodium hydroxide solution is 1-5 mol/L, and preferably 3-4 mol/L.

Preferably, the molar concentration of the ammonia water solution in the step (1) is 5-12 mol/L, and more preferably 8-10 mol/L.

Preferably, in the step (1), the reaction temperature is 40 to 80 ℃, and more preferably 50 to 60 ℃. The reaction time is 10 to 50 hours, and more preferably 40 to 48 hours.

Preferably, the protective atmosphere in the step (2) is one or more of nitrogen and inert gas, and the inert gas is preferably argon.

In the step (2), the divalent metal salt is one or a mixture of two of nitrate or acetate of nickel, cobalt and manganese.

Preferably, in the step (2), the molar ratio of the sodium borohydride to the boric acid to the divalent metal salt is 1-5: 10-20; more preferably 1-2: 6-10. The molar ratio of the divalent metal salt to the nickel-cobalt-manganese ternary material precursor is 1: 150-1: 40, and the preferable molar ratio is 1: 100-1: 50.

Preferably, in the step (2), the stirring time is 0.5-8 h.

Preferably, in the step (2), the calcining temperature is 300-600 ℃, and the calcining time is 2-10 h.

Compared with the prior art, the technical scheme of the invention has the following advantages:

according to the invention, the nickel-cobalt-manganese ternary precursor is coated with the metal boride and borate compound coating layer, and the coating layer compounded by the metal boride and the borate compound forms the coating layer with good structural stability and thermal stability and stable voltage platform, and can provide lithium ion and electron conduction, so that the conductivity of the material is improved. The composite coating improves the structure and performance of the material comprehensively. The nickel-cobalt-manganese ternary material synthesized by the modified precursor has obviously improved structural stability, cycle performance and rate capability.

The invention also provides a simple and effective modification method with low cost and easy realization, which can obviously improve the structural stability, thermal stability and electrochemical performance of the nickel-cobalt-manganese ternary material and has good application prospect.

Drawings

Fig. 1 is an SEM of the modified nickel-cobalt-manganese ternary precursor in example 1 of the present invention.

Detailed Description

The invention is further described with reference to the following figures and specific examples. It should be noted that the described embodiments illustrate only some of the embodiments of the invention, and should not be construed as limiting the scope of the claims. All other changes and modifications which can be made by one skilled in the art based on the embodiments of the present invention without inventive faculty are within the scope of the claims of the present application.

Example 1

A metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises a nickel-cobalt-manganese ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂And a coating layer Ni positioned on the surface of the nickel-cobalt-manganese ternary material precursor₂B/Ni₃(BO₃)₂The coating layer is a compound of metal boride and borate. The coating amount of the compound is precursor Ni_0.5Co_0.2Mn_0.3(OH)₂6% of the mass, and the thickness of the coating layer is 14 nm.

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL ethanol solution, adding 5 mmol Ni (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 1 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 1 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining and synthesizing the nickel-cobalt-manganese ternary positive electrode material. And taking the active material as the active material of the positive electrode material, and mixing the active material with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the massMixing according to the weight ratio of 8:1:1, taking N-methyl pyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring the mixture for 2 hours at the rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

FIG. 1 is an electron micrograph of the modified precursor in example 1, showing a particle size of about 8 μm. After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 168.8 mA h g^-1The capacity retention rate was 87.3%.

Comparative example 1

A preparation method of an uncoated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

And mixing and calcining the precursor and a lithium source to synthesize the nickel-cobalt-manganese ternary cathode material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 137.9 mA h g^-1The capacity retention rate was 64.5%.

Comparative example 2

A preparation method of a metal boride coated and modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL ethanol solution, adding 5 mmol Ni (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 2 mmol of NaBH was added₄Stirring for 2h, filtering, drying, calcining at 400 ℃ for 3h to obtain Ni₂[email protected]_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Ni₂[email protected]_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining and synthesizing the nickel-cobalt-manganese ternary positive electrode material. And thusMixing the active material serving as a positive electrode material with Acetylene Black (AB) serving as a conductive agent and polyvinylidene fluoride (PVDF) serving as a binder according to a mass ratio of 8:1:1, and placing the mixture in a small beaker by using N-methylpyrrolidone (NMP) as a solvent to stir for 2 hours at a rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 145.6 mA h g^-1The capacity retention rate was 75.9%.

Comparative example 3

A preparation method of a metal borate coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Sequentially adding 5 mmolNi (NO)₃)₂And 2 mmol of boric acid, grinding uniformly, and calcining at 400 ℃ for 3h to obtain Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining and synthesizing the nickel-cobalt-manganese ternary positive electrode material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 158.2 mA h g^-1The capacity retention rate was 79.2%.

Example 2

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL ethanol solution, adding 5 mmol Ni (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 0.5 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 1.5 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining and synthesizing the nickel-cobalt-manganese ternary positive electrode material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 162.9 mA h g^-1The capacity retention rate was 85.6%.

Example 3

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate are dissolved in 40mL of pure water and stirred to be dissolvedObtaining a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in the nitrogen atmosphere, simultaneously adding a 4mol/L sodium hydroxide solution and a 10 mol/L ammonia water solution, adjusting the pH of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL ethanol solution, adding 5 mmol Ni (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 1.5 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 0.5 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Ni₂B/Ni₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining and synthesizing the nickel-cobalt-manganese ternary positive electrode material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 800r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. In 200 cyclesThe specific discharge capacity is 159.6 mA h g^-1The capacity retention rate was 83%.

Example 4

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL ethanol solution, adding 5 mmol Co (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 1 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 1 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Co₂B/Co₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Co₂B/Co₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining to synthesize ternary material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 1000r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying the pole piece in the vacuum drying oven at 100 ℃ for 4h, and placing the pole piece in a glove box which is full of argon and has the water content and the oxygen content of less than 0.1ppm for 4h to reduce the adsorption of the pole piece in the transferring processThen assembled into a CR2032 type button cell in a glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 156.8 mA h g^-1The capacity retention rate was 79.2%.

Example 5

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.05mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.03mol of manganese sulfate in 50mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.5Co_0.2Mn_0.3(OH)₂。

(2) Taking 0.05mol Ni_0.5Co_0.2Mn_0.3(OH)₂Dispersing in 20 mL of aqueous solution, adding 10 mmol Co (NO) in sequence under nitrogen atmosphere₃)₂After dissolution, 2 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 2 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Co₂B/Co₃(BO₃)₂@Ni_0.5Co_0.2Mn_0.3(OH)₂。

Mixing Co₂B/Co₃(BO₃)₂@ Ni_0.5Co_0.2Mn_0.3(OH)₂Mixing with lithium source, calcining to synthesize ternary material. Mixing the active material with conductive agent Acetylene Black (AB) and binder polyvinylidene fluoride (PVDF) at a mass ratio of 8:1:1, and using N-methylpyrrolidone (NMP) as solventAnd placing the mixture into a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 1000r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h in the vacuum drying oven at 100 ℃, placing the pole piece in a glove box with the water content and the oxygen content of less than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 1C rate for 200 cycles. The specific discharge capacity after 200 cycles is 162.6 mA h g^-1The capacity retention rate was 85.3%.

Example 6

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.06mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.02mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.6Co_0.2Mn_0.2(OH)₂。

(2) Taking 0.05mol Ni_0.6Co_0.2Mn_0.2(OH)₂Dispersing in 20 mL of aqueous solution, and sequentially adding 5 mmol of NiSO under the nitrogen atmosphere₄After dissolution, 1 mmol of NaBH was added₄Stirring for 2h, filtering, drying, mixing with 1 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Ni₂B/Ni₃(BO₃)₂@Ni_0.6Co_0.2Mn_0.2(OH)₂。

Mixing Ni₂B/Ni₃(BO₃)₂@Ni_0.6Co_0.2Mn_0.2(OH)₂And (3) mixing and calcining a lithium source to synthesize the ternary material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 1000r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h in the vacuum drying oven at 100 ℃, placing the pole piece in a glove box with the water content and the oxygen content of less than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 3C rate for 300 cycles. The specific discharge capacity after 300 cycles is 136.1 mA h g^-1The capacity retention rate was 79.7%.

Example 7

The preparation method of the metal boride and borate composite coated modified nickel-cobalt-manganese ternary material precursor comprises the following steps:

(1) dissolving 0.06mol of nickel sulfate, 0.02mol of cobalt sulfate and 0.02mol of manganese sulfate in 40mL of pure water, stirring and dissolving to obtain a nickel-cobalt-manganese solution, then adding the nickel-cobalt-manganese solution into a reaction kettle at the speed of 5mL/min in a nitrogen atmosphere, simultaneously adding 4mol/L of sodium hydroxide solution and 10 mol/L of ammonia water solution, adjusting the pH value of the solution to 11-12, reacting for 48 hours at 50 ℃, filtering and drying to obtain a ternary material precursor Ni_0.6Co_0.2Mn_0.2(OH)₂。

(2) Taking 0.05mol Ni_0.6Co_0.2Mn_0.2(OH)₂Dispersing in 20 mL of aqueous solution, and sequentially adding 5 mmol of NiSO under the argon atmosphere₄After dissolution, 1 mmol of NaBH was added₄Stirring for 1h, filtering, drying, mixing with 0.5 mmol boric acid, grinding, calcining at 400 deg.C for 3h to obtain Ni₂B/Ni₃(BO₃)₂@Ni_0.6Co_0.2Mn_0.2(OH)₂。

Mixing Ni₂B/Ni₃(BO₃)₂@Ni_0.6Co_0.2Mn_0.2(OH)₂Mixing with lithium source, calcining to synthesize ternary material. And taking the active material as an active substance of the anode material, mixing the active substance with Acetylene Black (AB) as a conductive agent and polyvinylidene fluoride (PVDF) as a binder according to the mass ratio of 8:1:1, taking N-methylpyrrolidone (NMP) as a solvent, placing the mixture in a small beaker, and stirring and mixing the mixture for 2 hours at the rotating speed of 1000r/min to obtain slurry. Coating the slurry on a current collector aluminum foil by using an automatic coating machine, flatly placing the current collector aluminum foil on toughened glass, transferring the current collector aluminum foil to a vacuum drying oven at 85 ℃ for drying for 4h, preparing a pole piece with the diameter of 14mm by punching, drying for 4h at 105 ℃ in the vacuum drying oven, placing the pole piece in a glove box with the water content and the oxygen content both lower than 0.1ppm and filled with argon atmosphere for 4h to reduce the water absorbed by the pole piece in the transferring process, and then assembling the pole piece into a CR2032 type button cell in the glove box. The battery uses a pure metal lithium sheet with the diameter of 16mm and the thickness of 0.5mm as a negative electrode, and a porous polyethylene film with the diameter of 18mm and the model of Celgard2300 as a diaphragm.

After the battery is assembled and aged for 12 hours, the charging and discharging tests of different potentials are carried out. The sample was activated at 4.3V for 3 cycles at 0.1C and then cycled at 3C rate for 300 cycles. The specific discharge capacity after 300 cycles is 128.6 mA h g^-1The capacity retention rate was 72.7%.

The above description is only a basic description of the present invention, and any equivalent changes made according to the technical solution of the present invention should fall within the protection scope of the present invention.