阅读说明：本技术 一种硅碳负极材料及制备方法 (Silicon-carbon negative electrode material and preparation method thereof ) 是由 马越 白苗 汤晓宇 王鹤林 于 2021-08-04 设计创作，主要内容包括：本发明涉及一种硅碳负极材料及制备方法,质量百分比由以下组分组成：微米硅粉10％～50％,沥青90％～50％,以上组分质量百分比之和为100％；原料为微米级硅粉,价格低廉,通过高能球磨得到粒度均匀的纳米硅粉,能有效改善硅在循环过程的体积效应；球磨过程中加入分散剂用于抑制纳米硅粉团聚,实现有效分散；沥青与硅粉均匀混合,实现沥青衍生碳的均匀包覆,抑制硅在嵌锂、脱锂过程中的体积膨胀,同时提高了硅与集流体之间的电接触；最终提高硅碳负极材料用于锂离子电池的首次可逆容量,提高电池循环稳定性；本发明硅碳负极复合材料的制备方法,操作简单,成本低,易实现工业化。(The invention relates to a silicon-carbon cathode material and a preparation method thereof, wherein the silicon-carbon cathode material comprises the following components in percentage by mass: 10-50% of micron silicon powder and 90-50% of asphalt, wherein the sum of the mass percentages of the components is 100%; the raw material is micron-sized silicon powder, the price is low, and the nano silicon powder with uniform particle size is obtained through high-energy ball milling, so that the volume effect of silicon in the circulating process can be effectively improved; dispersing agent is added in the ball milling process to inhibit the agglomeration of the nano silicon powder and realize effective dispersion; the asphalt and the silicon powder are uniformly mixed, so that the asphalt derived carbon is uniformly coated, the volume expansion of silicon in the processes of lithium insertion and lithium removal is inhibited, and the electrical contact between the silicon and a current collector is improved; finally, the first reversible capacity of the silicon-carbon negative electrode material for the lithium ion battery is improved, and the cycling stability of the battery is improved; the preparation method of the silicon-carbon cathode composite material is simple to operate, low in cost and easy to realize industrialization.)

1. The silicon-carbon anode material is characterized by comprising the following components in percentage by mass: 10-50% of nano silicon powder and 90-50% of asphalt derived carbon, wherein the sum of the mass percentages of the components is 100%; wherein, the nano silicon powder is embedded in the asphalt derived carbon, and the granularity of the nano silicon powder is not more than 200 nm.

2. The silicon-carbon anode material according to claim 1, wherein: the precursor of the pitch-derived carbon is petroleum pitch with a softening point of 250 ℃.

3. A method for preparing the silicon-carbon anode material of claim 1 or 2, characterized by the steps of:

step 1: dispersing micron silicon powder in ethanol, adding a dispersing agent, uniformly mixing, adding into a ball milling tank, and carrying out ball milling to obtain a nano silicon powder ethanol mixture; the proportion of the silicon to the ethanol is 20 to 30 percent; the dispersant accounts for 0.5 to 1 percent of the mass of the silicon powder; the particle size of the nano silicon powder is not more than 200 nm;

step 2: weighing asphalt, adding the asphalt into the nano silicon powder ethanol mixture, and stirring to obtain a silicon asphalt mixture; the ratio of the nano silicon powder to the asphalt is 1: 10-1: 1;

and step 3: placing the silicon asphalt mixture into a spray dryer for spray drying to obtain a silicon asphalt spray intermediate; the air inlet temperature of spray drying is 150-190 ℃, and the air outlet temperature is 70-90 ℃;

and 4, step 4: preheating the silicon pitch spray intermediate in a coating machine to obtain a silicon-carbon precursor; the preheating: firstly heating to 600-700 ℃, then preserving heat for 1-2 h, then continuously heating to 750-850 ℃, then preserving heat for 2-4 h, wherein the heating speed is 5-10 ℃/min, and the heating atmosphere is inert gas;

and 5: sintering the silicon-carbon precursor at high temperature to obtain a silicon-carbon negative electrode material; the sintering temperature of the high-temperature sintering is 850-950 ℃, the heat preservation time is 1-3 h, and the heating atmosphere is inert gas.

4. The method of claim 3, wherein: the granularity of the micron silicon powder in the step 1 is not more than 5 mu m.

5. The method of claim 3, wherein: the dispersant is AMP-95 aminomethyl propanol.

6. The method of claim 3, wherein: the AMP-95 aminomethyl propanol comprises the following components: 2-amino-2-methyl-1-propanol, the concentration is not less than 89.0%; 2-methyl-2-methylamino-1-propanol, the concentration is not more than 7.0%; and water at a concentration of 5%.

7. The method of claim 3, wherein: in the step 1: the ball milling speed is 900r/min to 1200r/min, and the ball milling time is 2h to 6 h.

8. The method of claim 3, wherein: the high-temperature sintering adopts a rotary furnace.

Technical Field

The invention belongs to the technical field of lithium ion battery preparation, and relates to a silicon-carbon negative electrode material and a preparation method thereof.

Background

Lithium ion batteries have been widely used in the fields of portable consumer electronics, electric tools, medical electronics, and the like because of their excellent properties. Meanwhile, the method has good application prospect in the fields of pure electric vehicles, hybrid electric vehicles, energy storage and the like. The lithium ion battery commercialized at present mainly uses graphite as a negative electrode material. However, in recent years, the demand for energy density of batteries has been rapidly increasing in various fields, and development of lithium ion batteries with higher energy density has been strongly demanded. Therefore, the development of a negative electrode material with higher energy density is urgent.

The highest specific mass capacity of the silicon material can reach 4200mA h g^-1(Li₂₂Si₅) The lower lithium storage reaction voltage platform is the material which is known to be the highest theoretical specific volume of the negative electrode of the lithium ion battery at present. And the silicon material is environment-friendly, abundant in reserve and low in cost, so that the silicon-based negative electrode material is a novel high-energy material with great development prospect. However, the electronic conductivity and ionic conductivity of silicon are low, resulting in poor kinetics of electrochemical reactions; more importantly, the phase change and volume expansion of silicon in the lithiation process can generate larger stress, so that the electrode is broken and pulverized, the resistance is increased, and the cycle performance is suddenly reduced. The nano silicon and the carbonaceous material are compounded, so that the conductivity of the silicon-carbon cathode material can be improved, and the carbonaceous material can also be used as a buffer matrix to provide a certain buffer effect for the volume change of the silicon. However, the nano silicon has a large specific surface area and is easy to agglomerate, and the silicon in the obtained silicon-carbon composite material is often unevenly distributed, so that the improvement of the electrochemical performance of the negative electrode material is limited.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a silicon-carbon anode material and a preparation method thereof.

One of the purposes of the invention is to provide a silicon-carbon negative electrode material which can effectively improve the cycling stability of a battery;

the second purpose of the invention is to provide a preparation method of the silicon-carbon cathode material, which is simple to operate, low in cost and easy to realize industrialization.

Technical scheme

The silicon-carbon anode material is characterized by comprising the following components in percentage by mass: 10-50% of nano silicon powder and 90-50% of asphalt derived carbon, wherein the sum of the mass percentages of the components is 100%; wherein, the nano silicon powder is embedded in the asphalt derived carbon, and the granularity of the nano silicon powder is not more than 200 nm.

The precursor of the pitch-derived carbon is petroleum pitch with a softening point of 250 ℃.

The method for preparing the silicon-carbon negative electrode material is characterized by comprising the following steps:

step 1: dispersing micron silicon powder in ethanol, adding a dispersing agent, uniformly mixing, adding into a ball milling tank, and carrying out ball milling to obtain a nano silicon powder ethanol mixture; the proportion of the silicon to the ethanol is 20 to 30 percent; the dispersant accounts for 0.5 to 1 percent of the mass of the silicon powder; the particle size of the nano silicon powder is not more than 200 nm;

step 2: weighing asphalt, adding the asphalt into the nano silicon powder ethanol mixture, and stirring to obtain a silicon asphalt mixture; the ratio of the nano silicon powder to the asphalt is 1: 10-1: 1;

and step 3: placing the silicon asphalt mixture into a spray dryer for spray drying to obtain a silicon asphalt spray intermediate; the air inlet temperature of spray drying is 150-190 ℃, and the air outlet temperature is 70-90 ℃;

and 4, step 4: preheating the silicon pitch spray intermediate in a coating machine to obtain a silicon-carbon precursor; the preheating: firstly heating to 600-700 ℃, then preserving heat for 1-2 h, then continuously heating to 750-850 ℃, then preserving heat for 2-4 h, wherein the heating speed is 5-10 ℃/min, and the heating atmosphere is inert gas;

and 5: sintering the silicon-carbon precursor at high temperature to obtain a silicon-carbon negative electrode material; the sintering temperature of the high-temperature sintering is 850-950 ℃, the heat preservation time is 1-3 h, and the heating atmosphere is inert gas.

The granularity of the micron silicon powder in the step 1 is not more than 5 mu m.

The dispersant is AMP-95 aminomethyl propanol.

The AMP-95 aminomethyl propanol comprises the following components: 2-amino-2-methyl-1-propanol, the concentration is not less than 89.0%; 2-methyl-2-methylamino-1-propanol, the concentration is not more than 7.0%; and water at a concentration of 5%.

In the step 1: the ball milling speed is 900r/min to 1200r/min, and the ball milling time is 2h to 6 h.

The high-temperature sintering adopts a rotary furnace.

Advantageous effects

According to the silicon-carbon cathode material and the preparation method thereof, the raw material is micron-sized silicon powder, the price is low, and the nano silicon powder with uniform particle size is obtained through high-energy ball milling, so that the volume effect of silicon in the circulation process can be effectively improved; dispersing agent is added in the ball milling process to inhibit the agglomeration of the nano silicon powder and realize effective dispersion; the asphalt and the silicon powder are uniformly mixed, so that the asphalt derived carbon is uniformly coated, the volume expansion of silicon in the processes of lithium insertion and lithium removal is inhibited, and the electrical contact between the silicon and a current collector is improved; finally, the first reversible capacity of the silicon-carbon negative electrode material for the lithium ion battery is improved, and the cycling stability of the battery is improved; the preparation method of the silicon-carbon cathode composite material is simple to operate, low in cost and easy to realize industrialization.

The invention has the beneficial effects that:

1. the silicon-carbon cathode material is prepared from micron-sized silicon powder and is low in price, and the nano silicon powder with uniform particle size is obtained through high-energy ball milling, so that the volume effect of silicon in the circulating process can be effectively improved; dispersing agent is added in the ball milling process to inhibit the agglomeration of the nano silicon powder and realize effective dispersion; the asphalt and the silicon powder are uniformly mixed, so that the asphalt derived carbon is uniformly coated, the volume expansion of silicon in the processes of lithium insertion and lithium removal is inhibited, and the electrical contact between the silicon and a current collector is improved; finally, the first reversible capacity of the silicon-carbon negative electrode material for the lithium ion battery is improved, and the cycling stability of the battery is improved.

2. The preparation method of the silicon-carbon cathode material is simple to operate, low in cost and easy to realize industrialization.

Drawings

Fig. 1 is an SEM image of a silicon-carbon negative electrode material provided in example 1 of the present invention;

fig. 2 is an SEM cross-sectional view of a silicon-carbon negative electrode material provided in example 1 of the present invention;

FIG. 3 is a TEM image of a silicon-carbon anode material provided in example 1 of the present invention;

fig. 4 is a XRD test result of the silicon-carbon anode material provided in example 1 of the present invention;

fig. 5 shows TG test results of silicon carbon negative electrode materials provided in examples 1 and 2 of the present invention;

fig. 6 shows the capacity retention rate and coulombic efficiency of a lithium battery prepared from the silicon-carbon negative electrode composite material provided in example 1 of the present invention.

Fig. 7 shows the capacity retention rate and coulombic efficiency of a full battery obtained by matching the silicon-carbon negative electrode composite material provided in embodiment 1 of the present invention with NCM 811.

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

the invention adopts the technical scheme that the silicon-carbon cathode material comprises the following components in percentage by mass: 10-50% of nano silicon powder and 90-50% of asphalt derived carbon, wherein the sum of the mass percentages of the components is 100%; wherein the nano silicon powder is embedded in the asphalt derived carbon, the particle size of the nano silicon powder is not more than 200nm, and a precursor of the asphalt derived carbon is petroleum asphalt with a softening point of 250 ℃;

the embodiment of the invention provides a preparation method of a silicon-carbon negative electrode material, which is realized by the following steps:

step 1, weighing micron silicon powder, wherein the granularity of the micron silicon powder is not more than 5 microns, dispersing the micron silicon powder in ethanol, the proportion of silicon to ethanol is 20-30%, adding 0.5-1% of dispersing agent, wherein the dispersing agent is AMP-95 aminomethyl propanol, and the specific components are as follows: 2-amino-2-methyl-1-propanol, the concentration is not less than 89.0%; 2-methyl-2-methylamino-1-propanol, the concentration is not more than 7.0%; and water with the concentration of 5 percent, adding the mixture into a ball milling tank for ball milling after uniform mixing, wherein the ball milling rotation speed is 900r/min to 1200r/min, the ball milling time is 2h to 6h, and the granularity of the nano silicon powder obtained by ball milling is not more than 200nm to obtain a nano silicon powder ethanol mixture;

step 2, weighing asphalt, wherein the ratio of the silicon powder to the asphalt is 1: 10-1: 1, adding the nano silicon powder ethanol mixture obtained in the step 1 and stirring to obtain a silicon asphalt mixture;

step 3, placing the silicon asphalt mixture obtained in the step 2 into a spray dryer for spray drying, wherein the air inlet temperature of the spray drying is 150-190 ℃, the air outlet temperature is 70-90 ℃, and a silicon asphalt spray intermediate is obtained;

step 4, placing the silicon asphalt spray intermediate obtained in the step 3 into a coating machine for preheating, heating to 600-700 ℃, then preserving heat for 1-2 h, then continuing to heat to 750-850 ℃, then preserving heat for 2-4 h, wherein the heating speed is 5-10 ℃/min, and the heating atmosphere is inert gas, so as to obtain a silicon-carbon precursor;

and 5, sintering the silicon-carbon precursor prepared in the step 4 at high temperature by using a rotary furnace, wherein the sintering temperature is 850-950 ℃, the heat preservation time is 1-3 h, and the heating atmosphere is inert gas, so that the silicon-carbon cathode material is obtained.

Example 1

Step 1, weighing 1kg of micron silicon powder, dispersing the micron silicon powder in 3kg of ethanol, adding 10g of AMP-95 aminomethyl propanol, uniformly mixing, adding the mixture into a ball milling tank, and carrying out ball milling for 6 hours at the ball milling rotation speed of 900r/min to obtain a nano silicon powder ethanol mixture;

step 2, weighing 1kg of asphalt, adding the asphalt into the nano silicon powder ethanol mixture obtained in the step 1, and stirring to obtain a silicon asphalt mixture;

step 3, placing the silicon asphalt mixture obtained in the step 2 into a spray dryer for spray drying, wherein the air inlet temperature of the spray drying is 150 ℃, the air outlet temperature is 90 ℃, and a silicon asphalt spray intermediate is obtained;

step 4, placing the silicon asphalt spray intermediate obtained in the step 3 into a coating machine for preheating, heating to 600 ℃, then preserving heat for 2 hours, then continuing to heat to 750 ℃, and preserving heat for 3 hours, wherein the heating speed is 10 ℃/min, and the heating atmosphere is inert gas, so as to obtain a silicon-carbon precursor;

and 5, sintering the silicon-carbon precursor prepared in the step 4 at a high temperature, wherein the high-temperature sintering adopts a rotary furnace, the sintering temperature is 850 ℃, the heat preservation time is 3 hours, and the heating atmosphere is inert gas, so that the silicon-carbon cathode material is obtained.

The silicon-carbon negative electrode material obtained in step 5 of example 1 is subjected to electron microscope Scanning (SEM) tests, and as a result, spherical particles with different sizes can be seen as shown in fig. 1. The SEM cross section of the silicon carbon particles shows that the silicon carbon is uniformly mixed and a large number of large pores are formed in the middle, as shown in fig. 2. Further high resolution transmission scanning electron microscopy characterization (HRTEM) was performed, and as shown in fig. 3, it can be seen that silicon particles are uniformly distributed in the carbon substrate, and the lattice spacing of 0.31nm corresponds to the (111) crystal plane of silicon; carbon substrate has carbon microcrystals with lattice spacing of 0.39nm and amorphous carbon, which is characteristic of soft carbon derived from pitch.

When the silicon-carbon negative electrode material prepared in example 1 is subjected to an X-ray diffraction (XRD) test, as shown in fig. 4, a peak of silicon can be seen, which indicates that silicon is pure phase silicon with good crystallinity, has good structural consistency and no other impurities, and soft carbon obtained by pitch diffraction has substantially no peak.

Example 2

Step 1, weighing 1kg of micron silicon powder, dispersing the micron silicon powder in 4kg of ethanol, adding 5g of AMP-95 aminomethyl propanol, uniformly mixing, adding the mixture into a ball milling tank, and carrying out ball milling for 2 hours at the ball milling rotation speed of 1200r/min to obtain a nano silicon powder ethanol mixture;

step 2, weighing 3kg of asphalt, adding the asphalt into the nano silicon powder ethanol mixture obtained in the step 1, and stirring to obtain a silicon asphalt mixture;

step 3, placing the silicon asphalt mixture obtained in the step 2 into a spray dryer for spray drying, wherein the air inlet temperature of the spray drying is 190 ℃, the air outlet temperature is 70 ℃, and a silicon asphalt spray intermediate is obtained;

step 4, placing the silicon asphalt spray intermediate obtained in the step 3 into a coating machine for preheating, heating to 650 ℃, then preserving heat for 1.5h, then continuing to heat to 800 ℃, then preserving heat for 3h, wherein the heating speed is 8 ℃/min, and the heating atmosphere is inert gas, so as to obtain a silicon-carbon precursor;

and 5, sintering the silicon-carbon precursor prepared in the step 4 at a high temperature, wherein the high-temperature sintering adopts a rotary furnace, the sintering temperature is 900 ℃, the heat preservation time is 2 hours, and the heating atmosphere is inert gas, so that the silicon-carbon cathode material is obtained.

Example 3

Step 1, weighing 1kg of micron silicon powder, dispersing the micron silicon powder in 5kg of ethanol, adding 8g of AMP-95 aminomethyl propanol, uniformly mixing, adding the mixture into a ball milling tank, and carrying out ball milling for 4 hours at the ball milling rotation speed of 1000r/min to obtain a nano silicon powder ethanol mixture;

step 2, weighing 10kg of asphalt, adding the asphalt into the nano silicon powder ethanol mixture obtained in the step 1, and stirring to obtain a silicon asphalt mixture;

step 3, placing the silicon asphalt mixture obtained in the step 2 into a spray dryer for spray drying, wherein the air inlet temperature of the spray drying is 170 ℃, the air outlet temperature is 80 ℃, and a silicon asphalt spray intermediate is obtained;

step 4, placing the silicon asphalt spray intermediate obtained in the step 3 into a coating machine for preheating, heating to 700 ℃, then preserving heat for 1h, then continuing to heat to 850 ℃, and preserving heat for 4h, wherein the heating speed is 7 ℃/min, and the heating atmosphere is inert gas, so as to obtain a silicon-carbon precursor;

and 5, sintering the silicon-carbon precursor prepared in the step 4 at a high temperature, wherein the high-temperature sintering adopts a rotary furnace, the sintering temperature is 950 ℃, the heat preservation time is 1h, and the heating atmosphere is inert gas, so that the silicon-carbon cathode material is obtained.

Example 4

Step 1, weighing 1kg of micron silicon powder, dispersing the micron silicon powder in 4kg of ethanol, adding 5g of AMP-95 aminomethyl propanol, uniformly mixing, adding the mixture into a ball milling tank, and carrying out ball milling for 4 hours at the ball milling rotation speed of 1000r/min to obtain a nano silicon powder ethanol mixture;

step 2, weighing 7kg of asphalt, adding the asphalt into the nano silicon powder ethanol mixture obtained in the step 1, and stirring to obtain a silicon asphalt mixture;

step 3, placing the silicon asphalt mixture obtained in the step 2 into a spray dryer for spray drying, wherein the air inlet temperature of the spray drying is 180 ℃, the air outlet temperature is 85 ℃, and a silicon asphalt spray intermediate is obtained;

step 4, placing the silicon asphalt spray intermediate obtained in the step 3 in a coating machine for preheating, heating to 650 ℃, then preserving heat for 1.5h, then continuing to heat to 800 ℃, then preserving heat for 34h, wherein the heating speed is 5 ℃/min, and the heating atmosphere is inert gas, so as to obtain a silicon-carbon precursor;

and 5, sintering the silicon-carbon precursor prepared in the step 4 at a high temperature, wherein the high-temperature sintering adopts a rotary furnace, the sintering temperature is 900 ℃, the heat preservation time is 2.5 hours, and the heating atmosphere is inert gas, so that the silicon-carbon cathode material is obtained.

Thermogravimetric Test (TG): as shown in fig. 5, the silicon carbon negative electrode materials prepared in examples 1 and 2 were placed in a thermogravimetric analyzer and tested in an air atmosphere at a heating rate of 10 ℃/min, and it was found that the silicon content was about 34.6% in example 1 and about 55.0% in example 2.

And (3) testing the charge and discharge performance:

the silicon-carbon negative electrode material obtained in the embodiment 1 is prepared into a lithium ion battery negative electrode piece. The specific method comprises the steps of mixing and grinding the silicon-carbon material, the Super-P and the CMC according to the mass ratio of 8:1:1, using deionized water as a solvent, stirring for 12 hours, coating the mixture on a copper foil by using a scraper, drying in vacuum for 12 hours, slicing into a circular sheet with the diameter of 12mm, wherein the surface density of the negative electrode material loaded on a pole piece is about-1.2 mg cm^-2. The cell was set up in a glove box filled with high purity argon, both water and oxygen concentrations were less than 0.1 ppm. For the half cells, 2016 coin cells with metallic lithium foil as the counter electrode were assembled. Wherein the diaphragm adopts a Polyethylene (PE) film, and the electrolyte is 1.0M LiPF₆Dissolved in EC/DEC (1:1, Vol%) containing 5.0% FEC. After standing for 12h, the test was carried out by constant current charging and discharging at 0.5C, the charging limit voltage of the battery was 2.0V, and the discharging end voltage was 0.01V. The test results are shown in FIG. 6, the specific discharge capacity is up to 1250mA hg^-1The initial coulombic efficiency is about 78.5%, the average coulombic efficiency is kept 98.7%, and the capacity retention rate is as high as 85% at 100 circles. In addition, for a full cell, the silicon carbon negative electrode prepared in example 1 was first blended with graphite to obtain an average specific capacity of about 550mAh g^-1The negative electrode of (1). From industrial LiNi_0.8Co_0.1Mn_0.1O₂The (NCM811) electrode serves as the positive electrode.The positive electrode was prepared by mixing NCM811, Super-P and polyvinylidene fluoride binder (100: 1: 1.5) in N-methylpyrrolidone to a uniform slurry. The slurry was coated on an aluminum foil current collector and dried in vacuum at 120 ℃ for 12 h. The positive-negative electrode capacity ratio is about 1: 1.1. the charge-discharge voltage window is 2.8V-4.2V, and the current density is 0.5C. As shown in fig. 7, the initial coulombic efficiency is 91.6%, and the capacity retention rate is 82% after 2000 cycles, so that the silicon-carbon material prepared by the technical scheme of the invention is used as the negative electrode material of the lithium battery, and has the advantages of high initial coulombic efficiency, high capacity, good cycle stability and the like in terms of electrical properties.

The ball mill model adopted in the above embodiment is a WSP6 high-speed ball mill; the inert gas adopts nitrogen or argon; the granularity of the micron silicon powder is not more than 5 mu m; the dispersant is AMP-95 aminomethyl propanol: the concrete components are as follows: 2-amino-2-methyl-1-propanol, the concentration is not less than 89.0%; 2-methyl-2-methylamino-1-propanol, the concentration is not more than 7.0%; and water at a concentration of 5%.

The silicon-carbon cathode material provided by the invention has the advantages that the raw material is micron-sized silicon powder, the price is low, and the nano-silicon powder with uniform particle size is obtained through high-energy ball milling, so that the volume effect of silicon in a circulating process can be effectively improved; dispersing agent is added in the ball milling process to inhibit the agglomeration of the nano silicon powder and realize effective dispersion; the asphalt and the silicon powder are uniformly mixed, so that the asphalt derived carbon is uniformly coated, the volume expansion of silicon in the processes of lithium insertion and lithium removal is inhibited, and the electrical contact between the silicon and a current collector is improved; finally, the first reversible capacity of the silicon-carbon negative electrode material for the lithium ion battery is improved, and the cycling stability of the battery is improved; the preparation method of the silicon-carbon cathode material is simple to operate, low in cost and easy to realize industrialization.