阅读说明：本技术 一种锂离子电池负极材料及其制备方法 (Lithium ion battery cathode material and preparation method thereof ) 是由 李鹏 龙杰 吴苏州 陈俊孚 于 2021-07-05 设计创作，主要内容包括：本发明公开了一种锂离子电池负极材料及其制备方法,以改性纳米BN和改性纳米碳复合得到的材料为生长载体,通过在氮掺杂碳基体中均匀生成纳米花状ZnS,纳米花状ZnS不仅可以提供丰富的比表面积和较高的比电容,而且有利于改善循环稳定性,不会发生膨胀现象；材料的制备包括BN浆料的制备、改性纳米碳浆液的制备、复合材料基体粉末的制备及锂离子电池负极材料的制备四个步骤,制备工艺简单,制备得到的材料具有较高的比容量,且较优的循环性能,具有广阔的应用前景。(The invention discloses a lithium ion battery cathode material and a preparation method thereof, wherein a material obtained by compounding modified nano BN and modified nano carbon is taken as a growth carrier, and nano flower-shaped ZnS is uniformly generated in a nitrogen-doped carbon matrix, so that the nano flower-shaped ZnS not only can provide rich specific surface area and higher specific capacitance, but also is beneficial to improving the cycle stability and does not generate the expansion phenomenon; the preparation of the material comprises four steps of preparation of BN slurry, preparation of modified nano-carbon slurry, preparation of composite material matrix powder and preparation of a lithium ion battery negative electrode material, the preparation process is simple, and the prepared material has high specific capacity, excellent cycle performance and wide application prospect.)

1. A preparation method of a lithium ion battery cathode material is characterized by comprising the following steps:

(1) preparing boron nitride BN slurry: sequentially adding nanometer boron nitride BN, triethyl phosphate, polyvinyl butyral and glycerol into an ethanol solvent, performing ultrasonic dispersion for 1-2 hours, then performing ball milling and mixing for 12-15 hours, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding nano carbon powder into an ethanol solvent, carrying out ultrasonic dispersion for 2-3h, adding a surfactant, stirring and refluxing for 3-6h at the temperature of 80-110 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding the BN slurry obtained in the step (1) into the modified nano-carbon slurry obtained in the step (2), ultrasonically dispersing for 2-3h, stirring for 3-6h at the temperature of 60-90 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding powder preparation treatment, then preparing a biscuit through pressure forming at 30MPa, sintering and crushing the obtained biscuit, and grinding to obtain the composite material matrix powder;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding citric acid, tartaric acid and the composite material matrix powder obtained in the step (3) into a distilled water solvent, ultrasonically dispersing for 2-4h, adding zinc nitrate, ultrasonically dispersing for 1-3h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8-8.5, then adding ammonium thiosulfate, carrying out in-situ deposition reaction, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

2. The method for preparing the anode material of the lithium ion battery as claimed in claim 1, wherein the mass ratio of the nanometer BN, the triethyl phosphate, the polyvinyl butyral, the glycerol and the ethanol in the step (1) is 100:12-16:62-68:12-16: 420-500.

3. The method for preparing the negative electrode material of the lithium ion battery according to any one of claims 1 to 2, wherein the surfactant in the step (2) is one or more of sodium dodecyl benzene sulfonate, sodium secondary alkane sulfonate, sodium 3-alkenyl sulfonate or sodium 2-alkenyl sulfonate.

4. The preparation method of the negative electrode material of the lithium ion battery according to any one of claims 1 to 3, wherein the mass ratio of the nano carbon powder to the surfactant in the step (2) is 100: 12-16.

5. The preparation method of the negative electrode material of the lithium ion battery according to any one of claims 1 to 4, wherein the mass ratio of the BN slurry to the modified nano-carbon slurry in the step (3) is 7-10: 100.

6. The method for preparing the lithium ion battery anode material according to claim 1, wherein the sintering process parameters in the step (3) are as follows: the sintering temperature is 800-900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min.

7. The preparation method of the lithium ion battery anode material according to claim 1, wherein the particle size of the powder ground in the step (3) is less than or equal to 3 μm.

8. The preparation method of the negative electrode material of the lithium ion battery as claimed in claim 1, wherein the mass ratio of the composite material matrix powder, the citric acid, the tartaric acid, the zinc sulfate and the ammonium thiosulfate is 100:165-280:60-105:90-140: 40-65.

9. The preparation method of the lithium ion battery anode material according to claim 1, wherein the in-situ deposition reaction temperature in the step (4) is 80-90 ℃ and the reaction time is 5-10 h.

10. The lithium ion battery negative electrode material prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of battery material preparation, in particular to a lithium ion battery cathode material and a preparation method thereof.

Background

Along with the rapid development of industry, the demand for energy is higher and higher, but the excessive use of traditional fossil energy causes environmental pollution, and ecological environment and human existence are seriously damaged, and the development of a green and environment-friendly novel energy device is imminent, wherein a lithium ion battery has the advantages of high energy density, small self-discharge, high charging efficiency and the like, and is widely applied to electric automobiles and portable electronic products, and the research on the lithium ion battery with higher specific capacity and better cycle performance has important practical significance, and the negative electrode material in the lithium ion rechargeable battery has great influence on the battery.

Transition metal sulfide negative electrodes (e.g., CoS, Co)₉S₈ZnS, etc.) has very high actual specific capacitance, and is cheap and easily available, and is a lithium ion battery cathode material with great development potential, wherein the ZnS cathode material is paid much attention to, but the ZnS cathode material is easy to generate volume expansion phenomenon in the using process, thereby reducing cycle stability and rate capability, and thus restricting the development of the ZnS cathode material in the battery field. In view of the above disadvantages, patent document CN109301235A discloses ZnS @ SiO₂The preparation of/C high-performance cathode and its lithium/sodium storage application, the shell structure used is SiO₂and/C, the volume expansion of the ZnS negative electrode material is improved, and the cycle performance and the electrochemical dynamic characteristics are improved. The invention provides a lithium ion battery cathode material with completely different core-shell structures on the basis of the existing research.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a lithium ion battery negative electrode material and a preparation method thereof, wherein the material obtained by compounding modified nano BN and modified nano carbon is used as a growth carrier, so that the ZnS negative electrode material has good actual specific capacity and excellent electrochemical cycling stability, and does not expand.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a lithium ion battery negative electrode material comprises the following steps:

(1) preparation of BN slurry: sequentially adding nanometer BN, triethyl phosphate, polyvinyl butyral and glycerol into an ethanol solvent, performing ultrasonic dispersion for 1-2 hours, then performing ball milling and mixing for 12-15 hours, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding nano carbon powder into an ethanol solvent, carrying out ultrasonic dispersion for 2-3h, adding a surfactant, stirring and refluxing for 3-6h at the temperature of 80-110 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding the BN slurry obtained in the step (1) into the modified nano-carbon slurry obtained in the step (2), ultrasonically dispersing for 2-3h, stirring for 3-6h at the temperature of 60-90 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding powder preparation treatment, then preparing a biscuit through pressure forming at 30MPa, sintering and crushing the obtained biscuit, and grinding to obtain the composite material matrix powder;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding citric acid, tartaric acid and the composite material matrix powder obtained in the step (3) into a distilled water solvent, ultrasonically dispersing for 2-4h, adding zinc nitrate, ultrasonically dispersing for 1-3h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8-8.5, then adding ammonium thiosulfate, carrying out in-situ deposition reaction, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

Further, the mass ratio of the nanometer BN, the triethyl phosphate, the polyvinyl butyral, the glycerol and the ethanol in the step (1) is 100:12-16:62-68:12-16: 420-500.

Further, the surfactant in the step (2) is one or more of sodium dodecyl benzene sulfonate, sodium secondary alkane sulfonate, sodium 3-alkenyl sulfonate or sodium 2-alkenyl sulfonate.

Further, the mass ratio of the nano carbon powder to the surfactant in the step (2) is 100: 12-16.

Further, the mass ratio of the BN slurry to the modified nano-carbon slurry in the step (3) is 7-10: 100.

Further, the sintering process parameters in the step (3) are as follows: the sintering temperature is 800-900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min.

Furthermore, the particle size of the powder ground in the step (3) is less than or equal to 3 μm.

Further, the mass ratio of the composite material matrix powder to the citric acid to the tartaric acid to the zinc sulfate to the ammonium thiosulfate is 100:165-280:60-105:90-140: 40-65.

Further, the in-situ deposition reaction temperature in the step (4) is 80-90 ℃, and the reaction time is 5-10 h.

The invention also claims the lithium ion battery cathode material prepared by any one of the methods.

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

(1) according to the lithium ion battery cathode material provided by the invention, the material obtained by compounding the modified nanometer BN and the modified nanometer carbon is used as a growth carrier, and the nanometer flower-shaped ZnS is uniformly generated in the nitrogen-doped carbon matrix, so that the nanometer flower-shaped ZnS not only can provide rich specific surface area and higher specific capacitance, but also is beneficial to improving the cycle stability and does not expand; meanwhile, the nano flower-like ZnS has richer growth space, so that the modified composite matrix has better conductivity and abundant pore structures, and is beneficial to promoting the transfer of electrons and lithium ions, improving the actual specific capacity and enhancing the rate capability.

(2) The nanometer BN used by the invention is hexagonal boron nitride, is a wide-band-gap semiconductor, has extremely high thermal stability and chemical stability, simultaneously has higher elasticity, and can encapsulate gas molecules; the invention takes triethyl phosphate as a dispersing agent, polyvinyl butyral as an adhesive and glycerol as a plasticizer to modify nanometer BN, thereby further enhancing the performance of the material; meanwhile, the surface activity modification is carried out on the nano carbon powder, so that the active point position of the nano carbon powder is enhanced, the composite effect of the nano carbon powder and the modified nano BN is improved, the pore structure of the composite material is further enriched, the specific surface area of a matrix is improved, the strength and the elasticity of the framework are enhanced, and the phenomenon that the volume expansion is easy to occur in the use process of the ZnS negative electrode material is avoided.

(3) The preparation method of the lithium ion battery cathode material provided by the invention has the advantages that the preparation process is simple, and the prepared material has higher specific capacity, better cycle performance and wide application prospect.

Detailed Description

The present invention will be described in more detail with reference to specific preferred embodiments, but the present invention is not limited to the following embodiments.

It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention are commercially available.

Example 1

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparation of BN slurry: sequentially adding 100g of nano BN, 16g of triethyl phosphate, 68g of polyvinyl butyral and 16g of glycerol into 500g of ethanol solvent, performing ultrasonic dispersion for 1h, performing ball milling and mixing for 12h, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding 100g of nano carbon powder into 490g of ethanol solvent, performing ultrasonic dispersion for 2 hours, adding 12g of sodium dodecyl benzene sulfonate, stirring and refluxing for 3 hours at 90 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding 7g of BN slurry obtained in the step (1) into 100g of modified nano-carbon slurry obtained in the step (2), ultrasonically dispersing for 2h, stirring for 3h at 70 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding powder preparation treatment, then preparing a biscuit through pressure forming under 30MPa, sintering and crushing the obtained biscuit, and grinding to below 3 mu m to obtain the composite material matrix powder; wherein the sintering temperature is 900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 165g of citric acid, 60g of tartaric acid and 100g of the composite material matrix powder obtained in the step (3) into 450g of distilled water solvent, ultrasonically dispersing for 2h, adding 90g of zinc nitrate, ultrasonically treating for 1h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8, then adding 40g of ammonium thiosulfate, carrying out in-situ deposition reaction at 80 ℃ for 5h, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

Example 2

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparation of BN slurry: sequentially adding 100g of nanometer BN, 14g of triethyl phosphate, 65g of polyvinyl butyral and 14g of glycerol into 465g of ethanol solvent, performing ultrasonic dispersion for 1h, performing ball milling and mixing for 13h, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding 100g of nano carbon powder into 490g of ethanol solvent, performing ultrasonic dispersion for 3h, adding 14g of secondary alkane sodium sulfonate, stirring and refluxing for 5h at 100 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding 8g of BN slurry obtained in the step (1) into 100g of modified nano-carbon slurry obtained in the step (2), ultrasonically dispersing for 3h, stirring for 4h at 80 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding powder preparation treatment, then preparing a biscuit through pressure forming under 30MPa, sintering and crushing the obtained biscuit, and grinding to below 3 mu m to obtain the composite material matrix powder; wherein the sintering temperature is 850 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 200g of citric acid, 75g of tartaric acid and 100g of the composite material matrix powder obtained in the step (3) into 480g of distilled water solvent, ultrasonically dispersing for 3h, adding 110g of zinc nitrate, ultrasonically treating for 2h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8.5, then adding 48g of ammonium thiosulfate, carrying out in-situ deposition reaction at 85 ℃ for 8h, and filtering and washing sequentially after the reaction is finished to obtain the lithium ion battery negative electrode material.

Example 3

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparation of BN slurry: sequentially adding 100g of nano BN, 12g of triethyl phosphate, 63g of polyvinyl butyral and 12g of glycerol into 460g of ethanol solvent, performing ultrasonic dispersion for 1h, performing ball milling and mixing for 12h, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding 100g of nano carbon powder into 500g of ethanol solvent, performing ultrasonic dispersion for 2 hours, adding 16g of 3-sodium alkenyl sulfonate, stirring and refluxing for 5 hours at 100 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding the BN slurry (9g) obtained in the step (1) into the modified nano-carbon slurry (100g) obtained in the step (2), ultrasonically dispersing for 2 hours, stirring for 4.5 hours at 85 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding to prepare powder, then performing pressure forming under 30MPa to prepare a biscuit, sintering and crushing the biscuit, and grinding to below 3 mu m to obtain the composite material matrix powder; wherein the sintering temperature is 820 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 220g of citric acid, 95g of tartaric acid and 100g of the composite material matrix powder obtained in the step (3) into 650g of distilled water solvent, ultrasonically dispersing for 2h, adding 115g of zinc nitrate, ultrasonically treating for 1h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8, then adding 55g of ammonium thiosulfate, carrying out in-situ deposition reaction at 85 ℃ for 5h, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

Example 4

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparation of BN slurry: sequentially adding 100g of nanometer BN, 12g of triethyl phosphate, 62g of polyvinyl butyral and 12g of glycerol into 440g of ethanol solvent, performing ultrasonic dispersion for 2 hours, performing ball milling and mixing for 15 hours, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing modified nano carbon slurry: adding 100g of nano carbon powder into 465g of ethanol solvent, adding 16g of 2-sodium alkenyl sulfonate after ultrasonic dispersion for 2h, stirring and refluxing for 3h at 90 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(3) preparing composite material matrix powder: adding 10g of BN slurry obtained in the step (1) into 100g of modified nano-carbon slurry obtained in the step (2), ultrasonically dispersing for 2h, stirring for 3h at 70 ℃, then cooling to room temperature, sequentially performing centrifugation, drying and grinding to prepare powder, then performing pressure forming under 30MPa to prepare a biscuit, sintering and crushing the biscuit, and grinding to below 3 mu m to obtain the composite material matrix powder; wherein the sintering temperature is 900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(4) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 270g of citric acid, 100g of tartaric acid and the composite material matrix powder (100g) obtained in the step (3) into 650g of distilled water solvent, ultrasonically dispersing for 2h, adding 130g of zinc nitrate, ultrasonically treating for 1h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8, then adding 60g of ammonium thiosulfate, carrying out in-situ deposition reaction at 90 ℃ for 10h, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

Comparative example 1

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparation of BN slurry: sequentially adding 100g of nano BN, 16g of triethyl phosphate, 68g of polyvinyl butyral and 16g of glycerol into 500g of ethanol solvent, performing ultrasonic dispersion for 1h, performing ball milling and mixing for 12h, and performing vacuum defoaming to obtain the BN slurry;

(2) preparing composite material matrix powder: adding 7g of BN slurry obtained in the step (1) into 100g of nano carbon powder, ultrasonically dispersing for 2h, stirring for 3h at 70 ℃, then cooling to room temperature, sequentially carrying out centrifugation, drying and grinding to prepare powder, then carrying out pressure forming under 30MPa to prepare a biscuit, sintering and crushing the biscuit, and grinding to below 3 microns to obtain the composite material matrix powder; wherein the sintering temperature is 900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(3) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 165g of citric acid, 60g of tartaric acid and 100g of the composite material matrix powder obtained in the step (3) into 450g of distilled water solvent, ultrasonically dispersing for 2h, adding 90g of zinc nitrate, ultrasonically treating for 1h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8, then adding 40g of ammonium thiosulfate, carrying out in-situ deposition reaction at 80 ℃ for 5h, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

Comparative example 2

A preparation method of a lithium ion battery cathode material comprises the following preparation steps:

(1) preparing modified nano carbon slurry: adding 100g of nano carbon powder into 490g of ethanol solvent, performing ultrasonic dispersion for 2 hours, adding 12g of sodium dodecyl benzene sulfonate, stirring and refluxing for 3 hours at 90 ℃, and then cooling to room temperature to obtain the modified nano carbon slurry;

(2) preparing composite material matrix powder: adding 7g of nano BN into the modified nano carbon slurry (100g) obtained in the step (1), ultrasonically dispersing for 2h, stirring for 3h at 70 ℃, then cooling to room temperature, sequentially carrying out centrifugation, drying and grinding to prepare powder, then carrying out pressure forming under 30MPa to prepare a biscuit, sintering and crushing the obtained biscuit, and grinding to below 3 microns to obtain the composite material matrix powder; wherein the sintering temperature is 900 ℃, the pressure maintaining pressure is 30MPa, the heat preservation time is 1h, and the heating rate is 20 ℃/min;

(3) preparing a lithium ion battery negative electrode material: and (3) sequentially adding 165g of citric acid, 60g of tartaric acid and 100g of the composite material matrix powder obtained in the step (3) into 450g of distilled water solvent, ultrasonically dispersing for 2h, adding 90g of zinc nitrate, ultrasonically treating for 1h again, then dropwise adding ammonia water to adjust the pH value of the solution to 8, then adding 40g of ammonium thiosulfate, carrying out in-situ deposition reaction at 80 ℃ for 5h, and sequentially filtering and washing after the reaction is finished to obtain the lithium ion battery cathode material.

The materials prepared in the examples 1-4 and the comparative examples 1-2 are used as negative electrode active materials, acetylene black is used as a conductive agent, polyvinylidene fluoride is used as a binder, the materials are placed in N-methyl pyrrolidone to be uniformly mixed, then the mixture is coated on the surface of copper foil, and the copper foil is dried and punched into a circular electrode slice which is used as a lithium ion negative electrode; a lithium sheet is used as a positive electrode, a polypropylene microporous membrane is used as a diaphragm, 1mol/L LiPF6 solution is used as electrolyte, a CR2032 battery is assembled in an argon glove box, and then the electrochemical performance is tested according to GB/T18287-2013. The specific test results are shown in table 1.

TABLE 1

As can be seen from Table 1, the material prepared by the method has high discharge capacity and stable recycling performance.

Finally, it is to be noted that: the above examples do not limit the invention in any way. It will be apparent to those skilled in the art that various modifications and improvements can be made to the present invention. Accordingly, any modification or improvement made without departing from the spirit of the present invention is within the scope of the claimed invention.