CN115394990A - Preparation method of lithium battery silicon-carbon negative electrode material - Google Patents

Preparation method of lithium battery silicon-carbon negative electrode material Download PDF

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CN115394990A
CN115394990A CN202211123290.XA CN202211123290A CN115394990A CN 115394990 A CN115394990 A CN 115394990A CN 202211123290 A CN202211123290 A CN 202211123290A CN 115394990 A CN115394990 A CN 115394990A
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silicon
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lithium battery
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王建平
周凯
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Wuxi Sina New Material Technology Co ltd
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Abstract

The invention relates to the field of battery materials, in particular to a preparation method of a lithium battery silicon-carbon negative electrode material, which comprises the following steps: s1, carrying out surface modification pretreatment on a nano silicon material by adopting an alkoxy silane coupling agent; s2, carrying out in-situ polymerization on the surface of the surface-modified nano silicon material by using a polymer monomer to obtain a precursor; and S3, carbonizing the precursor under the protection of inert atmosphere to obtain the silicon-carbon composite material. The alkoxy silane coupling agent has a bridging effect between the interface of the nano silicon material and the polymer monomer, can ensure that the polymer monomer is uniformly polymerized on the surface of nano silicon material particles, and can obtain the silicon-carbon composite material with good uniformity of structure, particle size, composition and the like after carbonization. Due to in-situ polymerization of the polymer monomer, the pyrolytic carbon can better relieve mechanical stress generated by volume expansion of silicon, reduce the phenomena of pulverization and collapse of the negative electrode material, improve the conductivity of the negative electrode material, improve the electrical contact between the negative electrode material and a current collector and improve the cycle stability of the battery.

Description

Preparation method of lithium battery silicon-carbon negative electrode material
Technical Field
The invention belongs to the field of electrode material preparation, and particularly relates to a preparation method of a lithium battery silicon-carbon negative electrode material.
Background
As electronic devices are developed into the fields of miniaturization, intelligence, and multifunction, lithium batteries having smaller volumes and higher output powers are required, and batteries having larger capacities, lower costs, higher safety, and stability are required for the development of electric vehicles. The performance of lithium ion batteries mainly depends on positive and negative electrode materials, and the development of negative electrode materials with higher energy density is one of the current research focuses.
The silicon-based negative electrode material has high theoretical capacity (4200 mAh g) -1 ) And a more suitable de-intercalation potential (<0.5V) is the most promising high capacity anode material. However, in the process of lithium removal/insertion of silicon materials, large volume expansion (volume expansion of 100% -300%) exists, and the structural expansion and contraction change destroys the stability of the electrode structure, so that the silicon particles break and pulverize, the electrode material structure collapses and peels off, the electrode material loses electric contact, and finally the specific capacity of the negative electrode rapidly attenuates, and the cycle performance of the lithium battery is deteriorated. In 2009, the journal of the "energy source" (J Power Sources,2009, volume 189, 762) of the netherlands reports that silicon is compounded with a carbon material, so that the volume expansion effect of Si in the charging and discharging process can be effectively avoided, and the carbon material can improve the conductivity of Si, improve the electrical contact between an electrode active material and a current collector, and improve the cycle stability of Si.
At present, two-step methods are often adopted to prepare the Si/C composite nanomaterial, namely, si nanoparticles are dispersed in an organic carbon source solution to obtain a precursor, and then the precursor is pyrolyzed and carbonized at high temperature to obtain the Si/C composite nanomaterial. The organic carbon source is usually glucose, sucrose, citric acid, etc., and in order to increase the uniformity of the silicon material dispersed relative to the organic carbon source, some surfactants may be used (e.g., chinese patent nos. CN107204445A and CN 107359317A), and the surfactants are usually polyethylene glycol, polyacrylamide, stearic acid, sodium lauryl sulfate, sodium hexametaphosphate, cetyltrimethylammonium bromide, amphoteric triblock polymer formed by ethoxy-propoxy, etc. The surfactant is coated on the surface of the particles in the suspension by utilizing the characteristic that one end of a molecule is a hydrophilic group and the other end of the molecule is a hydrophobic group, so that the dispersion degree and the dispersion stability of the particles are improved.
In the method, the nano silicon powder material is required to be dispersed in an organic solvent (the organic solvent is used), the surfactant mainly separates particles in the suspension from the particles so as to improve the dispersion degree, the specific combination and connection effects between the organic carbon source and the silicon material are not realized, and the surfactant can also introduce impurity elements except silicon carbon. Therefore, the Si/C composite material prepared by the method still has insufficient uniformity in the aspects of structure, particle size, proportion and composition of Si (C) and the like.
Disclosure of Invention
Technical problem to be solved
In order to solve the problems in the prior art, the invention provides a preparation method of a silicon-carbon negative electrode material of a lithium battery, which is characterized in that an alkoxy silane coupling agent is added, so that on one hand, a bridging effect can be achieved in a mode of combining a silicon material and a high polymer by chemical bonds, and the uniformity of the structure, the particle size, the composition and the like of a Si/C composite material is improved; on the other hand, other impurity elements except silicon carbon are introduced, so that the silicon carbon negative electrode material with good electrochemical performance is obtained.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
a preparation method of a silicon-carbon negative electrode material of a lithium battery comprises the following steps:
s1, carrying out surface modification pretreatment on a nano silicon material by adopting an alkoxy silane coupling agent;
s2, carrying out in-situ polymerization on the surface of the surface-modified nano silicon material by using a polymer monomer to obtain a silicon-carbon composite material precursor;
and S3, carbonizing the silicon-carbon composite material precursor under the protection of inert atmosphere to obtain the silicon-carbon composite material.
In step S1, the alkoxysilane coupling agent and the nano-silicon material are mixed in a solvent according to a mass ratio of 1.
Preferably, the mixing is performed by dispersing the nano-silica material into deionized water, adding the alkoxysilane coupling agent, wherein each 1g of the nano-silica material is dispersed into about 10mL of deionized water, adding 0.01 to 0.11g of the alkoxysilane coupling agent, preferably each 1g of the nano-silica material is dispersed into about 10mL of deionized water, and then adding 0.01g, 0.05g or 0.11g of the alkoxysilane coupling agent.
Wherein the alkoxy silane coupling agent has the following structure:
Figure BDA0003847288790000031
wherein, X 1 、X 2 、X 3 Independently an alkoxy group, and R independently is a reactive functional group having affinity or reactivity with organic polymer molecules, such as alkoxy, mercapto, vinyl, epoxy, amide, aminopropyl, and the like. Preferably, X 1 、X 2 、X 3 Is the same alkoxy, such as methoxy, ethoxy, methoxyethoxy; or X 1 、X 2 、X 3 The middle part is methoxyl and the other part is ethoxyl; among them, R is preferably a hydrolyzable functional group containing no S or N, and more preferably a vinyl group.
As a preferred embodiment of the invention, the nano silicon material is Si or a mixture of Si and SiO, wherein SiO accounts for no more than 20% of the total mass of the nano silicon material. Preferably, the silicon material has a particle size of 30 to 300nm, preferably 50 to 100nm.
In a preferred embodiment of the present invention, in step S1, the alkoxysilane coupling agent is one or more selected from the group consisting of vinyltris (2-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane.
In a preferred embodiment of the present invention, in step S2, the polymer monomer is one or a mixture of several of aniline, pyrrole, and acrylonitrile.
As a preferred embodiment of the present invention, in step S2, the amount of the nano silicon material and the polymer monomer is 1 to 20 by mass ratio; preferably according to 1.
As a preferred embodiment of the invention, in step S3, the silicon-carbon composite material precursor is carbonized under argon atmosphere, the temperature rise rate is 1-10 ℃/min, the carbonization temperature is 600-1000 ℃, the heat preservation time is 5-15h, and the silicon-carbon composite material is prepared after cooling.
Wherein the heating rate is preferably 2 ℃/min, 5 ℃/min, 6 ℃/min or 10 ℃/min; the carbonization temperature is preferably 600 ℃, 800 ℃, 900 ℃ or 1000 ℃; the incubation time is preferably 5h, 10h, 12.5h or 15h.
The invention also provides a silicon-carbon negative electrode material which is prepared by the preparation method of any one of the embodiments.
(III) advantageous effects
The invention has the beneficial effects that:
(1) According to the preparation method, firstly, the surface of the nano silicon material is modified by using an alkoxy silane coupling agent, alkoxy contained in the alkoxy silane coupling agent is hydrolyzed into silanol in a solvent, the silanol and nano silicon particles can generate Si-O-Si covalent bonds, each alkoxy silane coupling agent monomer has three hydrolyzable alkoxy groups, and the three silanol formed after the three alkoxy groups are hydrolyzed can be condensed with the nano silicon particles to generate the Si-O-Si covalent bonds; after surface modification pretreatment, a layer of alkoxy silane coupling agent is tightly wrapped around the nano silicon particles. Then, in-situ polymerization is carried out on the polymer monomer on the surface of the pretreated nano silicon particles, the other end of the alkoxy silane coupling agent reacts with the high polymer to generate covalent bonds or physical winding, and the high polymer is tightly bound around the nano silicon particles. The alkoxy silane coupling agent has a bridging effect between the interface of the nano silicon material and the high polymer, and can ensure that the nano silicon material particles are wrapped by enough high polymer, so that the silicon-carbon composite material with good uniformity of structure, particle size, composition and the like can be obtained.
Preferably, the alkoxy silane coupling agent used in the invention is vinyl trialkoxy silane coupling agent, which is carbonized into Si and C during high-temperature carbonization treatment without introducing any impurity, so that the prepared silicon-carbon composite material has higher purity and better electrochemical performance.
(2) Compared with other methods which simply adopt a surfactant to enhance the dispersity, the alkoxy silane coupling agent used by the method has the function of specifically combining the nano silicon material and the high polymer in a chemical bond form, so that the polymer monomer is uniformly polymerized on the surface of the nano silicon particles, and finally the carbon layer is uniformly coated on the surface of the nano silicon particles through high-temperature carbonization.
(3) According to the invention, the nano silicon material and the pyrolytic carbon are compounded, and the most of the pyrolytic carbon is effectively coated on the surface of the nano silicon particles by setting the dosage ratio of the nano silicon particles to the polymer monomer. Compared with a silicon-carbon material prepared by simple mixing, the carbon coating layer is more uniform, and the pyrolytic carbon can better relieve the mechanical stress generated by volume expansion of silicon in the lithium removal/insertion process, reduce the phenomena of pulverization and collapse of the material, improve the conductivity of the negative electrode material, improve the electrical contact between an electrode layer and a current collector and improve the cycle stability of the battery.
When the silicon-carbon composite material prepared by the method is used as a lithium battery cathode, the energy density of the battery reaches 550-800mAh/g, and after 50 cycles, the capacity retention rate is 46-80%. Therefore, compared with the prior art, the silicon-carbon cathode material prepared by the invention can further buffer the volume expansion of the nano silicon material and improve the cycling stability of the battery.
Drawings
FIG. 1 is a flow chart of a method for preparing a silicon-carbon negative electrode material of a lithium battery.
FIG. 2 is a schematic diagram of the principle of alkoxy silane coupling agent in preparing silicon-carbon composite material.
FIG. 3 is a thermogravimetric plot of the silicon carbon composite in air of example 1.
Fig. 4 is a TEM image of the silicon carbon composite material in example 1.
Fig. 5 is a charge-discharge cycle curve of the button cell obtained in example 5.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.
Referring to fig. 1, the present invention provides a method for preparing a silicon-carbon negative electrode material for a lithium battery, which comprises:
s1, carrying out surface modification pretreatment on a nano silicon material by adopting an alkoxy silane coupling agent;
specifically, in water, an alkoxy silane coupling agent and the nano silicon particles are fully mixed according to a mass ratio of 1.
Wherein the water can be replaced by low-carbon alcohol proton solvents such as methanol, ethanol, ethylene glycol and the like. When mixing, the nanometer silicon material is dispersed into deionized water, then alkoxy silane coupling agent is added, wherein, every 1g of nanometer silicon material is dispersed into about 10mL of deionized water, and then 0.01-0.11 g of alkoxy silane coupling agent is added.
Wherein the alkoxy silane coupling agent has the following structure:
Figure BDA0003847288790000061
wherein, X 1 、X 2 、X 3 Independently an alkoxy group, and R independently is a reactive functional group having affinity or reactivity with the organic polymer, such as an alkoxy group, a mercapto group, a vinyl group, an epoxy group, an amide group, an aminopropyl group, and the like. Preferably, X 1 、X 2 、X 3 Is the same alkoxy, such as methoxy, ethoxy, methoxyethoxy; or X 1 、X 2 、X 3 The middle part is methoxyl and the other part is ethoxyl; among them, R is preferably a hydrolyzable functional group containing no S or N, and more preferably a vinyl group.
The principle of the alkoxy silane coupling agent in the invention can be combined with that shown in figure 2, in a protic solvent, alkoxy groups on alkoxy silane can be hydrolyzed into silanol, the silanol can generate Si-O-Si covalent bonds with nano-silicon particles, and three silanols formed after hydrolysis of three alkoxy groups are condensed with the nano-silicon particles to generate Si-O-Si covalent bonds, so that a layer of alkoxy silane coupling agent is tightly wrapped around the nano-silicon particles; and after the polymer monomer is polymerized on the surface of the modified silicon nano-particle in situ, the other end of the alkoxy silane coupling agent reacts with the high polymer to generate a covalent bond or physical winding, and the nano-silicon material is connected with the high polymer in a chemical bond form.
In the present invention, it is preferable that the alkoxysilane coupling agent is vinyltris (2-methoxyethoxy) silane, vinyltriethoxysilane or vinyltrimethoxysilane, which has a short chain length and a thin interface layer, and the vinyl group can form a strong covalent bond with the high polymer, while the alkoxy group can form a strong Si-O-Si bond with Si or SiO after hydrolysis, so that the polymer can be tightly bound to the outer periphery of the nano-silicon material.
S2, carrying out in-situ polymerization on the surface of the nano silicon material subjected to surface modification by using a polymer monomer to obtain a silicon-carbon composite material precursor;
specifically, the operation steps are as follows:
firstly adding a polymer monomer into a nano silicon particle aqueous solution containing an alkoxy silane coupling agent, then adding an initiator, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ overnight to obtain a precursor of the silicon-carbon composite material.
Wherein, the mass ratio of the nano silicon particles to the polymer monomer is 1-20, so that most pyrolytic carbon is effectively coated on the surface of the nano silicon particles.
And S3, carbonizing the precursor of the silicon-carbon composite material under the protection of inert atmosphere to obtain the silicon-carbon composite material.
Specifically, a precursor of the silicon-carbon composite material can be placed in a tubular furnace, argon is introduced as protective atmosphere, the heating rate is 1-10 ℃/min, the temperature is raised to 600-1000 ℃, and the temperature is kept for 5-15h; and naturally cooling to obtain the silicon-carbon composite material.
The characteristics and technical effects of the preparation method of the present invention are described below with reference to specific examples. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water, and dripping vinyl tri (2-methoxyethoxy) silane (CH) 2 ＝CH-Si(OCH 2 CH 2 OCH 3 ) 3 】0.01g；
(2) Adding 4g of aniline monomer into the aqueous solution, adding 1.2g of initiator ammonium persulfate, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ for one night to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor in Ar inert atmosphere for high-temperature carbonization (the heating rate is 2 ℃/min, the carbonization temperature is 1000 ℃, and the heat preservation time is 5 h), and then naturally cooling to obtain the silicon-carbon composite material.
As shown in fig. 3, which is a thermal weight graph of the product obtained in this example in air, it can be seen from fig. 3 that the silicon-carbon composite material has complete heat release at 600 ℃, and the final mass loss percentage is about 39%, which indicates that the mass fraction of pyrolytic carbon in the silicon-carbon composite material is about 39%.
As shown in fig. 4, which is a TEM image of the product obtained in this example, it can be seen that the surface of the silicon nanoparticles (black particles) is uniformly coated with a layer of pyrolytic carbon (gray matrix).
Example 2
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water, and dripping vinyl triethoxysilane (CH) 2 ＝CH-Si(OCH 2 CH 3 ) 3 】0.05g；
(2) Adding 6g of aniline monomer into the aqueous solution, adding 1.8g of initiator ammonium persulfate, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ for one night to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor in Ar inert atmosphere for high-temperature carbonization (the heating rate is 5 ℃/min, the carbonization temperature is 1000 ℃, and the heat preservation time is 10 h), and then naturally cooling to obtain the silicon-carbon composite material.
Example 3
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water, and dripping vinyl tri (2-methoxyethoxy) silane (CH) 2 ＝CH-Si(OCH 2 CH 2 OCH 3 ) 3 】0.11g；
(2) Adding 8g of aniline monomer into the aqueous solution, adding 2.4g of initiator ammonium persulfate, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ for one night to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor into Ar inert atmosphere for high-temperature carbonization (the heating rate is 10 ℃/min, the carbonization temperature is 1000 ℃, and the heat preservation time is 15 h), and then naturally cooling to obtain the silicon-carbon composite material.
Example 4
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water, and dripping vinyl trimethoxy silane (CH) 2 ＝CH-Si(OCH 3 ) 3 】0.01g；
(2) Adding 4g of pyrrole monomer into the aqueous solution, then adding 1.2g of initiator ammonium persulfate, reacting in an ice-water bath for 3h, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ overnight to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor into Ar inert atmosphere for high-temperature carbonization (the heating rate is 2 ℃/min, the carbonization temperature is 800 ℃, and the heat preservation time is 5 h), and then naturally cooling to obtain the silicon-carbon composite material.
Comparative example 1
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water;
(2) adding 4g of aniline monomer into the aqueous solution, adding 1.2g of initiator ammonium persulfate, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ overnight to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor in Ar inert atmosphere for high-temperature carbonization (the heating rate is 2 ℃/min, the carbonization temperature is 1000 ℃, and the heat preservation time is 5 h), and then naturally cooling to obtain the silicon-carbon composite material.
Comparative example 2
A silicon carbon material for a lithium battery cathode and a preparation method thereof comprise the following steps:
(1) dispersing 1g of nano silicon particles into 10ml of deionized water, and dripping surfactant lauryl sodium sulfate [ C ] 12 H 25 SO 4 Na】0.01g；
(2) Adding 4g of aniline monomer into the aqueous solution, adding 1.2g of initiator ammonium persulfate, reacting in an ice-water bath for 3 hours, centrifuging, removing supernatant, and drying the obtained solid in an oven at 80 ℃ for one night to obtain a precursor of the silicon-carbon composite material;
(3) and (3) putting the silicon-carbon composite material precursor into Ar inert atmosphere for high-temperature carbonization (the heating rate is 2 ℃/min, the carbonization temperature is 1000 ℃, and the heat preservation time is 5 h), and then naturally cooling to obtain the silicon-carbon composite material.
This comparative example was prepared by replacing vinyltriethoxysilane in step (1) of example 1 with sodium lauryl sulfate, a surfactant. See example 1 for additional work.
Assembled battery testing
The silicon-carbon composites prepared in example 1, comparative example 1 and comparative example 2 were tested as negative electrodes of lithium ion batteries.
According to the silicon-carbon composite material: super P: mixing CMC and SBR according to the mass ratio of 80.
An electrode plate loaded with a silicon-carbon composite material is used as a working electrode, a round metal lithium plate with the diameter of 14mm is used as a counter electrode, and lithium hexafluorophosphate LiPF with the concentration of 1mol/L, which is formed by mixing vinylene carbonate EC, dimethyl carbonate DMC and methyl ethyl carbonate EMC according to the mass ratio of 1 6 The mixed solution is taken as electrolyte, a circular polypropylene film with the diameter of 16mm is taken as a diaphragm, the battery is assembled in a glove box protected by argon atmosphere, and an electrochemical performance test is carried out on a LAND multi-channel battery program-controlled tester, wherein the charging and discharging voltage is 0.05-1.5V; the current density was 100mA/g.
Fig. 5 shows the charge-discharge cycle curve of the test cell. As can be seen from the graph, the initial charge capacity of the product obtained in example 1 was 735.8mAh/g, the initial coulombic efficiency was 77.7%, and after 50-week cycles, the charge capacity of the battery was 536mAh/g, and the capacity retention rate was 72.8%.
The initial charge capacity of the product obtained in comparative example 1 was 727.8mAh/g, the initial coulombic efficiency was 75.5%, and after 50-week cycling, the charge capacity of the battery was 354.5mAh/g, the capacity retention rate was 48.7%, and the capacity retention rate was significantly lower than that of example 1.
The initial charge capacity of the product obtained in comparative example 2 was 783.2mAh/g, the initial coulombic efficiency was 63.8%, the charge capacity of the battery after 50-week cycles was 486.1mAh/g, and the capacity retention rate was only 62.1%, which was significantly lower than that of example 1.
In the preparation method, the high polymer is connected with the nano silicon particles by utilizing the functional group of the alkoxy siloxane coupling agent, after carbonization, the pyrolytic carbon layer is uniformly coated on the surface of the nano silicon particles, the uniform carbon layer can better absorb/relieve the volume expansion of silicon in the charging and discharging processes, the silicon material is coated to isolate the electrolyte, the direct contact between the silicon material and the electrolyte is avoided, the negative electrode is prevented from cracking and peeling off due to the volume expansion of the silicon material, the structural stability of the SEI film is improved, and the cycling stability of the battery is improved. As shown in FIG. 5, when the silicon-carbon composite material prepared by the invention is used as a negative electrode material of a lithium battery, the energy density of the battery reaches 550-800mAh/g, and after 50 cycles, the capacity retention rate is 46-80%.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. But any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A preparation method of a silicon-carbon negative electrode material of a lithium battery is characterized by comprising the following steps:
s1, carrying out surface modification pretreatment on a nano silicon material by adopting an alkoxy silane coupling agent;
s2, carrying out in-situ polymerization on the surface of the surface-modified nano silicon material by using a polymer monomer to obtain a silicon-carbon composite material precursor;
and S3, carbonizing the silicon-carbon composite material precursor under the protection of inert atmosphere to obtain the silicon-carbon composite material.
2. The method for preparing the silicon-carbon anode material for the lithium battery as claimed in claim 1, wherein in step S1, the alkoxysilane coupling agent and the nano-silicon material are mixed in a solvent according to a mass ratio of 1.
3. The method for preparing the silicon-carbon anode material of the lithium battery as claimed in claim 1, wherein in step S1, the alkoxy silane coupling agent is selected from one or more of vinyltris (2-methoxyethoxy) silane, vinyltriethoxysilane and vinyltrimethoxysilane.
4. The method for preparing the silicon-carbon anode material for the lithium battery as claimed in claim 1, wherein in step S2, the mass ratio of the nano silicon material to the polymer monomer is 1.
5. The method for preparing the silicon-carbon anode material of the lithium battery as claimed in claim 1, wherein in the step S2, the polymer monomer is one or a mixture of aniline, pyrrole and acrylonitrile.
6. The method for preparing the silicon-carbon anode material for the lithium battery as claimed in claim 1, wherein in the step S3, the silicon-carbon composite material precursor is carbonized under the argon atmosphere at a temperature rise rate of 1-10 ℃/min at a carbonization temperature of 600-1000 ℃ for 5-15h, and is cooled to obtain the silicon-carbon composite material.
7. A method for preparing a silicon-carbon negative electrode material for a lithium battery, which is prepared by the preparation method of any one of claims 1 to 6.
CN202211123290.XA 2022-09-15 2022-09-15 Preparation method of lithium battery silicon-carbon negative electrode material Pending CN115394990A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116666610A (en) * 2023-07-31 2023-08-29 江苏正力新能电池技术有限公司 Silicon-carbon negative electrode material and preparation method and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116666610A (en) * 2023-07-31 2023-08-29 江苏正力新能电池技术有限公司 Silicon-carbon negative electrode material and preparation method and application thereof
CN116666610B (en) * 2023-07-31 2023-09-29 江苏正力新能电池技术有限公司 Silicon-carbon negative electrode material and preparation method and application thereof

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