CN112768666A - Lithium ion battery silicon-carbon negative electrode material and preparation process and equipment thereof - Google Patents

Lithium ion battery silicon-carbon negative electrode material and preparation process and equipment thereof Download PDF

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CN112768666A
CN112768666A CN202110136458.XA CN202110136458A CN112768666A CN 112768666 A CN112768666 A CN 112768666A CN 202110136458 A CN202110136458 A CN 202110136458A CN 112768666 A CN112768666 A CN 112768666A
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silicon
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言伟雄
袁建陵
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Zhuzhou Fullad Technology Co ltd
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Abstract

The invention discloses a silicon-carbon negative electrode material of a lithium ion battery and a preparation process and equipment thereof, wherein the negative electrode material comprises a base material, and nano silicon and nano carbon which are mixed and deposited on the surface of the base material, the base material is a carbon material, the nano silicon and the nano carbon are mixed and deposited on the surface of the base material through a plasma enhanced chemical vapor deposition process, the base material is in a fluidized motion state in a deposition area in the plasma enhanced chemical vapor deposition process, the plasma enhanced chemical vapor deposition process is carried out in a fluidized plasma vapor deposition furnace, a positive plate, a negative plate and a stirring feeding mechanism are arranged in the fluidized plasma vapor deposition furnace, and the base material is in fluidized circulating motion in the deposition area under the vibration action of the negative plate and the action of the stirring feeding mechanism. According to the invention, the nano carbon and the nano silicon are mixed and deposited on the surface of the base material, and the carbon coating layer is formed on the surface of the nano silicon, so that the performance of the silicon-carbon cathode material is improved.

Description

Lithium ion battery silicon-carbon negative electrode material and preparation process and equipment thereof
Technical Field
The invention relates to the technical field of lithium ion battery cathode materials, in particular to a lithium ion battery silicon-carbon cathode material and a preparation process and equipment thereof.
Background
The lithium ion battery is a mature secondary battery, and with the continuous progress and development of society, the requirements of people on the negative electrode material of the lithium ion battery are higher and higher, and the traditional graphite negative electrode material cannot further meet the miniaturization requirements of electronic equipment and the high-power and high-energy density requirements of the vehicle battery because the capacity is close to the theoretical capacity of 372 mAh/g. The silicon-carbon negative electrode material is an advanced lithium ion battery negative electrode material capable of replacing a graphite negative electrode material, and the market share of the silicon-carbon negative electrode material is rapidly increasing.
The existing silicon-carbon cathode material preparation process generally adopts a high-energy grinding process to prepare silicon oxide nanoparticles in a silicon-carbon cathode material, and as the nano silicon oxide and a carbon material are in a free state, the phenomenon of agglomeration of the nano silicon oxide cannot be solved, so that the nano silicon oxide cannot be uniformly distributed in the carbon material, and the combination of the nano silicon oxide particles and the carbon is not tight or the bonding force is not strong.
Disclosure of Invention
The invention aims to provide a silicon-carbon cathode material of a lithium ion battery aiming at the defects in the prior art, the cathode material comprises a substrate, and simple substance nano silicon particles and nano carbon deposited on the surface of the substrate, wherein the substrate is in a fluidized flow state in the deposition process, and the nano silicon and the nano carbon can be uniformly and firmly distributed on the surface of the substrate by adopting a plasma enhanced chemical vapor deposition process.
According to the invention, the nano carbon is deposited in the process of depositing the nano silicon, and the nano silicon is isolated by the nano carbon, so that the phenomenon that the nano silicon forms a film to block an ion channel along with the increase of the deposition amount of the silicon can be prevented, the capacity of the base material can be fully exerted, on the other hand, the nano carbon isolates the nano silicon, the deposited silicon on the surface of the base material can be always kept in a nano particle state, and the local excessive expansion of the deposited silicon is reduced to the lowest level, so that the deposition amount of the nano silicon is greatly improved, namely, the energy density of the lithium ion battery is greatly improved on the premise of ensuring excellent comprehensive performance of the lithium ion battery including important indexes such as multiplying power, circulation, high and low temperatures.
The invention also aims to provide the preparation process of the silicon-carbon cathode material of the lithium ion battery, which has the advantages of simple process, uniform and consistent prepared cathode material, large-scale industrial production and realization of industrialization.
The purpose of the invention is realized by the following technical scheme:
a silicon-carbon cathode material of a lithium ion battery comprises a base material and nano silicon and nano carbon which are mixed and deposited on the surface of the base material, the base material is a carbon material, the nano silicon and the nano carbon are mixed and deposited on the surface of the base material by a plasma enhanced chemical vapor deposition process, in the plasma enhanced chemical vapor deposition process, the base material is in a fluidized motion state in a deposition area, the plasma enhanced chemical vapor deposition process is carried out in a fluidized plasma vapor deposition furnace, the fluidized plasma gas-phase deposition furnace is internally provided with a positive plate, a negative plate and a stirring and feeding mechanism, a deposition area is arranged between the positive plate and the negative plate, the negative plate has the function of vibration material conveying, the stirring and feeding mechanism is used for uniformly mixing the base materials and conveying the base materials to the upper part of the negative plate from the lower part of the negative plate, the base material is in fluidization circulating motion in the deposition area under the action of the vibration of the negative plate and the action of the stirring and feeding mechanism.
Furthermore, the vibration frequency and the vibration amplitude of the negative plate are respectively and independently adjustable, the stirring and feeding mechanism is a rotary stirring mechanism, the rotating speed is independently adjustable, and the base material is fluidized and circularly moved and continuously deposited in the deposition area under the coordination of the vibration action of the negative plate and the action of the stirring and feeding mechanism.
Further, the base material is at least one of graphene, carbon nanosheets, carbon fibers, carbon nanotubes, artificial graphite, natural graphite, mesophase microspheres, soft carbon and hard carbon.
Furthermore, the nano silicon is granular and has the granularity of 1-200 nm.
Further, the nanocarbon is in a granular shape and/or a film shape.
According to the invention, the nanocarbon and the nano silicon are mixed and deposited on the surface of the base material, and the carbon coating layer is formed on the surface of the nano silicon, so that the carbon coating layer can be used for buffering stress generated when the nano silicon expands, a buffer space is provided for the expansion of the nano silicon, the expansion effect of the silicon is further reduced, and the cycle performance of the silicon-carbon cathode material is further improved.
A preparation process of the silicon-carbon negative electrode material of the lithium ion battery comprises the following steps:
s1, placing a base material into a fluidized plasma vapor deposition furnace, and vacuumizing the deposition furnace;
s2, heating the deposition furnace, and making the base material perform fluidized circulating motion in a deposition area under the vibration action of a negative plate and the action of a stirring and feeding mechanism;
s3, introducing diluent gas into the deposition furnace, switching on a plasma generator, then alternately adding silicon source gas and carbon source gas in a time-sharing manner, depositing nano silicon and nano carbon on the surface of the substrate, depositing a carbon coating film after the deposition of the nano silicon is finished, and obtaining a product A after the deposition is finished;
and S4, screening and filtering the product A to obtain the lithium ion battery silicon-carbon cathode material B1.
Further, the step S4 includes performing coating treatment on the B1, where the coating treatment is liquid phase coating, and the liquid phase coated B1 is dried, carbonized, sieved, and filtered to obtain the lithium ion battery silicon carbon negative electrode material B2.
Further, the pressure in the fluidized plasma vapor deposition furnace is 0.01-2 torr in the step S1, and the temperature of the deposition furnace is 350-600 ℃ in the step S2.
Further, when the nano silicon is deposited in the step S3, the volume ratio of the diluent gas to the silicon source gas is 0.2-6: 1, the flow rate of the silicon source gas is 2-50L/min, and the single deposition time of the nano silicon is 0.1-100 hours; when the nano carbon is deposited, the volume ratio of the diluent gas to the carbon source gas is 0.2-6: 1, the flow rate of the carbon source gas is 2-50L/min, the single deposition time of the nano carbon is 0.1-100 hours, and the pressure in the fluidized plasma vapor deposition furnace is 2-10 torr.
Further, the silicon source gas in step S3 includes SiH4、SiHCl3、SiH2Cl2The carbon source gas comprises at least one of methane, ethylene, acetylene.
Further, the diluent gas in step S3 includes at least one of hydrogen, nitrogen, argon, and helium.
Further, the plasma generator used by the fluidized plasma vapor deposition furnace comprises a capacitive radio frequency power supply with direct current bias, namely the direct current power supply is connected with a radio frequency power supply load capacitor in parallel, the negative electrode of the direct current power supply is electrically connected with a negative plate, and the negative plate is contacted with the substrate.
The lithium ion battery silicon-carbon negative electrode material is formed by mixing or blending lithium ion battery silicon-carbon negative electrode materials B1 and B2 in any proportion.
The lithium ion battery silicon-carbon cathode material is formed by mixing or blending lithium ion battery silicon-carbon cathode materials B1 and B2 and the lithium ion battery carbon cathode material in any proportion.
The utility model provides a used equipment of lithium ion battery silicon carbon negative electrode material preparation technology, equipment is fluidization plasma gaseous deposition stove, be equipped with feed inlet and discharge gate on the deposition stove furnace body, the furnace body outside is equipped with electric heating element, is equipped with positive plate and negative plate inside the furnace body, and the positive plate is established in the negative plate top, keeps certain operating distance between positive plate and the negative plate, be plasma gaseous deposition district between positive plate and the negative plate, connect vibrating device on the negative plate, have the defeated material function of vibration, the negative plate below is equipped with stirring feed mechanism, and stirring feed mechanism carries the powder of negative plate below to the negative plate top, the substrate has realized the substrate at the circulation of deposit district and the continuous deposition of deposition stove to the substrate under the coordination of the vibration of negative plate and stirring feed mechanism effect.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the deposited silicon has excellent nanometer characteristics through the fluidization movement of the base material in the deposition process, namely, the deposited silicon is uniformly distributed on the surface of the base material in the form of nanometer particles, and gaps are formed among the particles, so that the deposited silicon is effectively inhibited from forming a film on the surface of the base material to block the contact of lithium ions and the base material; on the other hand, the deposited silicon is uniformly distributed on the surface of the base material in the form of nano particles, so that local over expansion of silicon element in the silicon-carbon negative electrode material in the lithium ion battery can be effectively inhibited, and the service life of the lithium ion battery is prolonged.
According to the invention, the nano carbon is mixed and deposited in the deposition process of the nano silicon, the nano silicon is isolated by using the nano carbon, the growth of nano silicon particles is prevented, the deposited silicon on the surface of the base material is always kept in a nano state, the deposition proportion of the nano silicon can be greatly improved, and the energy density of the lithium ion battery is greatly improved; on the other hand, the nano-silicon and the nano-carbon are mixed and deposited on the base material, and the nano-carbon provides a buffer space for the expansion of the nano-silicon, so that the service life of the lithium ion battery is further prolonged.
The invention adopts the plasma enhanced chemical vapor deposition process, so that the nano silicon and the nano carbon are firmly bonded with the substrate, and the nano silicon, the nano carbon and the substrate form a relative position relationship, thereby limiting the dissociation of the nano silicon and the nano carbon and solving the problem of agglomeration of the nano silicon due to the dissociation. The invention adopts surface deposition, has wide distribution area of nano silicon and large reaction area with electrolyte, and greatly improves the energy density of the lithium ion battery on the premise of ensuring the excellent comprehensive performance of the lithium ion battery including important indexes such as multiplying power, circulation, high temperature and low temperature and the like.
Drawings
FIG. 1 is a schematic structural view of a fluidized plasma vapor deposition furnace with a vertical stirring and feeding mechanism;
FIG. 2 is a schematic structural view of a fluidized plasma vapor deposition furnace with a horizontal stirring and feeding mechanism;
FIG. 3 is an electron microscope image of the morphological effect of fluidized plasma vapor deposition nano-silicon;
FIG. 4 is a graph of the dispersion performance of fluidized plasma vapor deposition of nano-silicon;
wherein, 1 is the negative plate, 2 is the electric heating element, 3 is the positive plate, 4 is the furnace body, 4001 is the feed inlet, 4002 is the discharge gate, 5 is stirring feed mechanism.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following specific examples.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
Example 1
As shown in fig. 1 and 2, the present embodiment provides a fluidized plasma vapor deposition furnace, a feed inlet 4001 and a discharge outlet 4002 are arranged on a furnace body 4, an electric heating element 5 is arranged outside the furnace body 4, a positive plate 3 and a negative plate 1 are arranged inside the furnace body 4, the positive plate 3 is arranged above the negative plate 1, a certain working distance is kept between the positive plate 3 and the negative plate 1, a plasma vapor deposition region is arranged between the positive plate 3 and the negative plate 1, a parallel space or an approximately parallel space is arranged between the positive plate 3 and the negative plate 1, and the negative plate 1 is connected with a vibrating device, so that the furnace has a vibrating material conveying function. The stirring and feeding mechanism 2 is arranged below the negative plate 1, wherein the stirring and feeding mechanism can be a vertical stirring and feeding mechanism or a horizontal stirring and feeding mechanism, as shown in fig. 1 and fig. 2 respectively, the stirring and feeding mechanism 5 conveys powder below the negative plate 1 to the position above the negative plate 1, and under the coordination of the vibration action of the negative plate 1 and the action of the stirring and feeding mechanism 5, the circulating flow of the base material in a deposition area and the continuous deposition of the base material by the deposition furnace are realized.
In the embodiment, the plasma generator used in the deposition furnace is a capacitive radio frequency power supply with direct current bias, and the direct current power supply is connected in parallel with a radio frequency power supply load capacitor, that is, the positive electrode of the direct current power supply is electrically connected with the positive plate 3, the negative electrode of the direct current power supply is electrically connected with the negative plate 1, and the negative plate 1 is in contact with the substrate.
Specifically, the working process of the fluidized plasma vapor deposition furnace provided by the embodiment is as follows:
the base material enters the deposition furnace from the feed inlet 4001, is conveyed to the position above the negative plate 1 through the stirring and feeding mechanism 5, and is fluidized and circulated in a deposition area under the coordination of the vibration action of the negative plate 1 and the action of the stirring and feeding mechanism 5, and then enters a time-sharing deposition process of nano silicon or nano carbon;
setting the flow rates of diluent gas, silicon source gas and carbon source gas and the single deposition time of nano silicon and nano carbon; in this embodiment, nano-silicon is deposited first, a diluent gas for depositing nano-silicon is added into a deposition furnace, a plasma generator is switched on, then a silicon source gas is added, performing nano-silicon deposition on the surface of the base material, closing the silicon source gas and the diluent gas in sequence when the single deposition time is up, then depositing nano-carbon, adding the diluent gas for depositing the nano-carbon into the deposition furnace, then adding the carbon source gas, and (3) carrying out nano-carbon deposition on the surface of the substrate, closing the carbon source gas and the diluent gas in sequence when the single deposition time is up, depositing nano-silicon again, circulating the processes, realizing the process of depositing nano-silicon or nano-carbon alternately in a time-sharing manner until the silicon deposition amount reaches the set requirement, finally depositing a nano-carbon coating film, keeping a certain distance between the substrate on the negative plate 1 and the positive plate 3 all the time in the deposition process, and discharging the substrate with the nano-silicon and the nano-carbon deposited on the surface from a discharge hole 4002 after the deposition of the substrate in a deposition area is finished.
Example 2
The embodiment provides a preparation process of a silicon-carbon cathode material of a lithium ion battery, wherein the weight of silicon accounts for about 10% of the total weight of the cathode material, the preparation process is completed based on a fluidized plasma vapor deposition furnace in embodiment 1, and a time-sharing deposition European style is adopted, and the preparation process specifically comprises the following steps:
s1, putting 85kg of base material into a fluidized plasma vapor deposition furnace, wherein the base material is artificial graphite particles, D50 is 15 mu m, and vacuumizing the deposition furnace until the pressure in the furnace is 0.01-2 torr;
s2, electrifying an electric heating element, heating the deposition furnace to 500 ℃, enabling the negative plate 1 to be in a vibration working state, adjusting the rotating speed of the feeding and stirring mechanism 5 to the rotating speed required by the process, conveying powder below the negative plate 1 to the negative plate 1 by the stirring and feeding mechanism 5, enabling the negative plate 1 to convey the base material to a deposition area through vibration conveying, and enabling the base material to be in a fluidized circulating motion state in the deposition area under the rotating action of the stirring and feeding mechanism 5 and the vibrating action of the negative plate;
s3, depositing nano silicon and nano carbon alternately in a time-sharing manner, firstly depositing the nano silicon, introducing diluent gas hydrogen into the furnace, switching on a plasma generator, then adding silicon source gas silane, wherein the flow rate of silane is 20L/min, the flow rate of hydrogen is 30L/min, the volume ratio of hydrogen to silane is 1.5:1, the single deposition time of the nano silicon is 20 minutes, the deposition time of 20 minutes is up, and sequentially closing the silane and the hydrogen; sequentially adding nitrogen and acetylene to deposit nano carbon, wherein the acetylene flow is 10L/min, the nitrogen flow is 15L/min, the volume ratio of the nitrogen to the acetylene is 1.5:1, the single deposition time of the nano carbon is 10 minutes, the deposition time of 10 minutes is up, then depositing nano silicon, and sequentially closing the acetylene and the nitrogen; sequentially adding hydrogen and silane, keeping the flow and the time unchanged, depositing the nano carbon instead of the nano silicon after 20 minutes, circulating the process, and depositing the nano silicon and the nano carbon in turn in a time-sharing manner until the cumulative time of depositing the nano silicon reaches 6.7 hours and the cumulative deposition amount of the silicon reaches 10 kg; finally, depositing a carbon coating film, sequentially closing silane and hydrogen, sequentially adding nitrogen and acetylene, keeping the flow unchanged, ensuring that the deposition time of the carbon coating film is 3.3 hours and 3.3 hours later, the accumulated deposition time of the nano carbon reaches 6.8 hours, the accumulated deposition amount of the carbon reaches 5kg, and obtaining a product A-1 after the deposition is finished; the silicon-carbon ratio in the product A-1 is 10:90, the total weight is 100 kg;
s4, discharging the deposited product A-1 from a discharge hole 4002, screening and filtering the product A-1, and removing lumps generated in the deposition process to obtain 100kg of the lithium ion battery silicon-carbon negative electrode material B1-1 with silicon content of about 10%.
The nano silicon on the surface of the lithium ion battery cathode material B1 substrate prepared by the embodiment is granular, the granularity is 20-80 nm, and the silicon-carbon ratio is 10: 90.
Example 3
The embodiment provides a preparation process of a silicon-carbon cathode material of a lithium ion battery, wherein the weight of silicon accounts for about 20% of the total weight of the cathode material, the preparation process is completed based on a fluidized plasma vapor deposition furnace in the embodiment 1, and a time-sharing deposition mode is adopted, and the preparation process specifically comprises the following steps:
s1, putting 70kg of base material into a fluidized plasma gas-phase deposition furnace, wherein the base material is natural crystalline flake graphite particles, D50 is 11 mu m, and vacuumizing the deposition furnace until the pressure in the furnace is 0.01-2 torr;
s2, electrifying an electric heating element, heating the deposition furnace to 500 ℃, enabling the negative plate 1 to be in a vibration working state, adjusting the rotating speed of the stirring and feeding mechanism 5 to the rotating speed required by the process, conveying powder below the negative plate 1 to the negative plate 1 by the stirring and feeding mechanism 5, enabling the negative plate 1 to convey the base material to a deposition area through vibration conveying, and enabling the base material to be in a fluidized circulating motion state in the deposition area under the rotating action of the stirring and feeding mechanism 5 and the vibrating action of the negative plate;
s3, depositing nano silicon and nano carbon alternately in a time-sharing manner, firstly depositing the nano silicon, introducing diluent gas hydrogen into the furnace, switching on a plasma generator, then adding silicon source gas silane, wherein the flow rate of silane is 20L/min, the flow rate of hydrogen is 30L/min, the volume ratio of hydrogen to silane is 1.5:1, the single deposition time of the nano silicon is 20 minutes, the deposition time of 20 minutes is up, and sequentially closing the silane and the hydrogen; sequentially adding nitrogen and acetylene to deposit nano carbon, wherein the acetylene flow is 6L/min, the nitrogen flow is 9L/min, the volume ratio of the nitrogen to the acetylene is 1.5:1, the single deposition time of the nano carbon is 10 minutes, the deposition time of 10 minutes is up, then depositing nano silicon, and sequentially closing the acetylene and the nitrogen; sequentially adding hydrogen and silane, keeping the flow and time unchanged, depositing the nano carbon instead of the nano silicon after 20 minutes, circulating the process, and depositing the nano silicon and the nano carbon in turn in a time-sharing manner until the cumulative time of depositing the nano silicon reaches 13.3 hours and the cumulative deposition amount of the silicon reaches 20 kg; finally, depositing a carbon coating film, sequentially closing silane and hydrogen, sequentially adding nitrogen and acetylene, keeping the flow unchanged, wherein the deposition time is 9 hours, namely 9 hours, the accumulated deposition time of the nano carbon reaches 22.3 hours, the accumulated deposition amount of the carbon reaches 10kg, and obtaining a product A-2 after the deposition is finished; the silicon-carbon ratio in the product A-2 is 20:80, the total weight is 100 kg;
s4, discharging the deposited product A-2 from a discharge hole 4002, screening and filtering the product A-2, and removing lumps generated in the deposition process to obtain 100kg of the lithium ion battery silicon-carbon negative electrode material B1-2 with the silicon content of about 20%.
The nano silicon on the surface of the base material B1-2 of the lithium ion battery silicon-carbon negative electrode material prepared by the embodiment is granular, the granularity is 25-80 nm, and the silicon-carbon ratio is 20: 80.
Example 4
In this embodiment, the lithium ion battery silicon-carbon negative electrode material B1-2 in embodiment 3 is further subjected to liquid phase coating, and the liquid phase coating used in this embodiment is asphalt coating, and the specific steps are as follows:
carrying out liquid phase coating treatment on a silicon-carbon negative electrode material B1-2 of the lithium ion battery, carrying out vacuum thermal stirring and mixing on asphalt powder and a solvent, so that asphalt is dissolved in the solvent, wherein the weight ratio of the total carbon content of the asphalt and the solvent to B1-2 is 4: 100, uniformly mixing the asphalt solvent and the B1-2 in vacuum, drying, carbonizing, screening and filtering to obtain 104kg of lithium ion battery silicon carbon negative electrode material B2.
In this embodiment, the liquid-phase-coated pitch carbon is coated on the surface of B1-2 in a thin film form, so that a coating leak point of plasma vapor deposition can be repaired, the surface of the coating layer is dense, side reactions caused by contact between nano-silicon and an electrolyte can be effectively prevented, the service life of the battery can be prolonged, and the silicon-carbon ratio of the lithium ion battery silicon-carbon negative electrode material prepared in this embodiment is 20: 84.
The lithium ion battery silicon-carbon negative electrode material prepared in the embodiment 2-4 is used as a working electrode, a lithium sheet is used as a counter electrode, 1mol/L LiPF6 and EC and DEC mixed solution with the volume ratio of 1:1 are used as electrolyte, a battery is assembled in an argon atmosphere glove box, and the battery is pressed, sealed and fully placed.
The electrochemical performance data obtained when the lithium ion battery silicon carbon negative electrode material prepared by the method is used for a lithium ion battery is shown in table 1.
TABLE 1
Figure BDA0002927118450000081
As can be seen from the table one, when the silicon carbon negative electrode material prepared by the technology of the present invention is used in a lithium ion battery, the first effect and the 50-cycle capacity retention rate are higher, and the silicon carbon negative electrode of example 4 after liquid phase coating is improved in the first effect and the 50-cycle capacity retention rate compared with the silicon carbon negative electrode material of example 3 without liquid phase coating.
The lithium ion battery silicon-carbon negative electrode materials B1 and B2 can be mixed or blended at any proportion, and can also be mixed or blended with carbon negative electrode materials at any proportion to form various silicon-carbon negative electrode material products.
It should be understood that the above examples are only for clearly illustrating the technical solutions of the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (15)

1. The silicon-carbon cathode material of the lithium ion battery is characterized by comprising a base material, and nano silicon and nano carbon which are mixed and deposited on the surface of the base material, the base material is a carbon material, the nano silicon and the nano carbon are mixed and deposited on the surface of the base material by a plasma enhanced chemical vapor deposition process, in the plasma enhanced chemical vapor deposition process, the base material is in a fluidized motion state in a deposition area, the plasma enhanced chemical vapor deposition process is carried out in a fluidized plasma vapor deposition furnace, the fluidized plasma gas-phase deposition furnace is internally provided with a positive plate, a negative plate and a stirring and feeding mechanism, a deposition area is arranged between the positive plate and the negative plate, the negative plate has the function of vibration material conveying, the stirring and feeding mechanism is used for uniformly mixing the base materials and conveying the base materials to the upper part of the negative plate from the lower part of the negative plate, the base material is in fluidization circulating motion in the deposition area under the action of the vibration of the negative plate and the action of the stirring and feeding mechanism.
2. The silicon-carbon anode material for the lithium ion battery as claimed in claim 1, wherein the vibration frequency and the vibration amplitude of the anode plate are independently adjustable, the stirring and feeding mechanism is a rotary stirring mechanism, the rotation speed is independently adjustable, and the base material makes fluidization and cyclic motion in the deposition area under the coordination of the vibration action of the anode plate and the stirring and feeding mechanism.
3. The silicon-carbon anode material for the lithium ion battery according to claim 1, wherein the substrate is at least one of graphene, carbon nanosheets, carbon fibers, carbon nanotubes, artificial graphite, natural graphite, mesophase microspheres, soft carbon and hard carbon.
4. The silicon-carbon anode material for the lithium ion battery according to claim 1, wherein the nano silicon is granular and has a particle size of 1-200 nm.
5. The silicon-carbon anode material for the lithium ion battery as claimed in claim 1, wherein the nanocarbon is in a granular and/or film form.
6. The preparation process of the silicon-carbon anode material of the lithium ion battery as claimed in any one of claims 1 to 5, characterized by comprising the following steps:
s1, placing a base material into a fluidized plasma vapor deposition furnace, and vacuumizing the deposition furnace;
s2, heating the deposition furnace, and making the base material perform fluidized circulating motion in a deposition area under the vibration action of a negative plate and the action of a stirring and feeding mechanism;
s3, introducing diluent gas into the deposition furnace, switching on a plasma generator, then alternately adding silicon source gas and carbon source gas in a time-sharing manner, depositing nano silicon and nano carbon on the surface of the substrate, depositing a carbon coating film after the deposition of the nano silicon is finished, and obtaining a product A after the deposition is finished;
and S4, screening and filtering the product A to obtain the lithium ion battery silicon-carbon cathode material B1.
7. The preparation process of claim 6, wherein the step S4 further comprises coating the B1 with a liquid phase coating, and the liquid phase coated B1 is dried, carbonized, sieved and filtered to obtain the lithium ion battery silicon carbon negative electrode material B2.
8. The process according to claim 6, wherein the pressure in the fluidized plasma vapor deposition furnace in step S1 is 0.01 to 2 Torr, and the temperature in the deposition furnace in step S2 is 350 to 600 ℃.
9. The process according to claim 6, wherein the volume ratio of the diluent gas to the silicon source gas is 0.2-6: 1, the flow rate of the silicon source gas is 2-50L/min, and the single deposition time of the nano-silicon is 0.1-100 hours when the nano-silicon is deposited in step S3; when the nano carbon is deposited, the volume ratio of the diluent gas to the carbon source gas is 0.2-6: 1, the flow rate of the carbon source gas is 2-50L/min, the single deposition time of the nano carbon is 0.1-100 hours, and the pressure in the fluidized plasma vapor deposition furnace is 2-10 torr.
10. The process of claim 6, wherein the silicon source gas in step S3 comprises SiH4、SiHCl3、SiH2Cl2The carbon source gas comprises at least one of methane, ethylene, acetylene.
11. The process of claim 6, wherein the diluent gas in step S3 is at least one of hydrogen, nitrogen, argon, and helium.
12. The process of claim 6, wherein the plasma generator of the fluidized plasma vapor deposition furnace comprises a capacitive RF power source with DC bias, i.e., a DC power source is connected in parallel with a RF power source load capacitor, the negative pole of the DC power source is electrically connected with a negative plate, and the negative plate is in contact with the substrate.
13. The lithium ion battery silicon-carbon negative electrode material is characterized by being formed by mixing or blending lithium ion battery silicon-carbon negative electrode materials B1 and B2 in any proportion.
14. The lithium ion battery silicon-carbon negative electrode material is characterized by being formed by mixing or blending lithium ion battery silicon-carbon negative electrode materials B1 and B2 and a lithium ion battery carbon negative electrode material in any proportion.
15. The utility model provides a used equipment of lithium ion battery silicon carbon negative electrode material preparation technology, its characterized in that, equipment is fluidization plasma gaseous deposition stove, be equipped with feed inlet and discharge gate on the deposition stove furnace body, the furnace body outside is equipped with electric heating element, is equipped with positive plate and negative plate inside the furnace body, and the positive plate is established in the negative plate top, keeps certain working distance between positive plate and the negative plate, be plasma gaseous deposition district between positive plate and the negative plate, vibrating device is connected to the negative plate, has the defeated material function of vibration, the negative plate below is equipped with stirring feed mechanism, and stirring feed mechanism carries the powder of negative plate below to the negative plate top. The base material realizes the circulation flow of the base material in the deposition area and the continuous deposition of the base material of the deposition furnace under the coordination of the vibration action of the negative plate and the action of the stirring feeding mechanism.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113215552A (en) * 2021-04-23 2021-08-06 株洲弗拉德科技有限公司 Method for preparing coating powder by adopting plasma vapor deposition process

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113215552A (en) * 2021-04-23 2021-08-06 株洲弗拉德科技有限公司 Method for preparing coating powder by adopting plasma vapor deposition process

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