CN114649496A - Preparation device and method of silicon composite material - Google Patents
Preparation device and method of silicon composite material Download PDFInfo
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- CN114649496A CN114649496A CN202210309172.1A CN202210309172A CN114649496A CN 114649496 A CN114649496 A CN 114649496A CN 202210309172 A CN202210309172 A CN 202210309172A CN 114649496 A CN114649496 A CN 114649496A
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
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- H01M4/0421—Methods of deposition of the material involving vapour deposition
- H01M4/0428—Chemical vapour deposition
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/26—Deposition of carbon only
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/4417—Methods specially adapted for coating powder
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/442—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using fluidised bed process
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- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides a preparation device and a preparation method of a silicon composite material. The invention provides a preparation device of a silicon composite material, which comprises a reaction unit, a gas inlet arranged at the bottom of the reaction unit and a gas outlet arranged at the top of the reaction unit; at least one crushing unit is arranged in the reaction unit and comprises a plurality of crushing members arranged in parallel, and each crushing member comprises a first baffle, a second baffle and a guide pipe. The preparation device and the preparation method provided by the invention can effectively improve the uniformity of the silicon material surface coating layer, improve the cycle performance and the rate capability of the lithium ion battery, and can be used for producing the silicon composite material.
Description
Technical Field
The invention relates to a preparation device and a preparation method of a silicon composite material, and relates to the technical field of battery materials.
Background
In recent years, lithium ion batteries have been considered to be the most promising energy storage devices due to their higher operating voltage and energy density, longer cycle life, and good safety performance. With the rapid development of human society, portable chargers, electric vehicles, and artificial intelligence have put high demands on energy density, cycle life, and safety performance. However, the capacity of the graphite serving as the cathode material of the conventional lithium ion battery is low, so that the improvement of the capacity of the lithium ion battery is limited, and compared with the graphite, silicon has over 10 times of theoretical capacity, and the theoretical capacity is close to 4000mAh/g, so that the silicon is a candidate material for improving the capacity of the lithium ion battery. However, in the cycle process, the silicon conductivity is poor, the volume expansion is severe (300%), and a Solid Electrolyte Interface (SEI) film is repeatedly formed and damaged, so that the cycle performance of the lithium ion battery is poor, and the practical application of silicon is limited.
Coating a silicon material is one of effective strategies for improving the electrochemical performance of a silicon anode, for example, coating a carbon layer on the silicon surface helps to improve the conductivity, flexibility and stability of an SEI film, can effectively prevent consumption and pulverization of internal silicon particles, and can also endow a silicon-carbon composite material with new performance and application by introducing heteroatoms into the carbon layer, such as sulfur doping, nitrogen doping and phosphorus doping, so that the conductivity of the carbon layer can be further improved. However, the existing coating method is complex, high in cost and not easy to prepare on a large scale, and the electrochemical performance of the prepared silicon composite material needs to be further improved.
By adopting the fluidized bed chemical vapor deposition method, the high fluidization of the nano silicon material in the reactor and the efficient heat and mass transfer between the reaction gas and the silicon particles are beneficial to improving the uniformity of the coating layer and improving the production of the silicon composite material, however, in the reaction process, the silicon material particles are easy to agglomerate, the reaction gas and the agglomerates are easy to contact to form bubbles, the gas-solid contact efficiency is influenced, the coating effect of the silicon material particles is influenced, and the coating layer has poor thickness controllability and poor uniformity. The fluidized quality can be effectively improved by arranging the inner member in the fluidized bed reaction unit, but the improvement effect of the inner members with different structures on the fluidized quality is different, so that how to further improve the fluidized quality and how to improve the coating uniformity of the silicon material are one of the problems which are continuously concerned by the technical personnel in the field.
Disclosure of Invention
The invention provides a preparation device and a preparation method of a silicon composite material, which are used for improving the coating uniformity of the surface of a silicon material and improving the cycle performance and the rate performance of a lithium ion battery.
The invention provides a preparation device of a silicon composite material, which comprises a reaction unit, a gas inlet arranged at the bottom of the reaction unit and a gas outlet arranged at the top of the reaction unit;
at least one crushing unit is arranged in the reaction unit, and the crushing unit comprises a plurality of crushing members which are arranged in parallel;
the crushing member comprises a first baffle, a second baffle and a flow guide pipe, the first baffle and the second baffle are oppositely arranged and form a first opening and a second opening which are mutually communicated, the first opening faces the gas outlet, the second opening faces the gas inlet, and the first baffle and the second baffle are provided with a plurality of through holes; the honeycomb duct is located between the first baffle and the second baffle, and the setting direction of the honeycomb duct is perpendicular to the direction of the gas inlet towards the gas outlet.
In one specific embodiment, the reaction unit is provided with a first crushing unit and a second crushing unit in sequence from the side close to the gas inlet to the side close to the gas outlet, the included angle between the crushing members in the first crushing unit and the crushing members in the second crushing unit is alpha, and the included angle is more than 0 degrees and less than alpha and less than 180 degrees.
In a specific embodiment, the first baffle plate comprises a first upper baffle plate and a first lower baffle plate which are connected with each other, the second baffle plate comprises a second upper baffle plate and a second lower baffle plate which are connected with each other, the first upper baffle plate and the second upper baffle plate are arranged in parallel, and the included angle between the first lower baffle plate and the second lower baffle plate is 15-90 degrees;
the first upper baffle and the second upper baffle are respectively provided with an upper through hole, the first lower baffle and the second lower baffle are respectively provided with a lower through hole, and the upper through holes and the lower through holes are sequentially arranged in a staggered manner.
In one embodiment, the ratio of the total area of the upper through holes to the total area of the first and second upper baffles is not greater than 10%; the ratio of the total area of the lower through holes to the total area of the first lower baffle and the second lower baffle is not more than 5%.
In a specific embodiment, the vertical distance between the first upper baffle and the second upper baffle is 40-500 mm; the height of the first upper baffle and the second upper baffle is 20-400 mm.
In a specific embodiment, the crushing unit is at a vertical distance of not less than 100mm from the gas inlet.
In a specific implementation mode, the device is still including setting up the separation element that crushing unit is close to gas outlet one side, the separation element is including being close to first separation baffle of gas inlet one side and being close to the second separation baffle of gas outlet one side, first separation baffle encloses and forms the third opening towards gas inlet and the fourth opening towards gas outlet, the third opening place plane with the contained angle of first separation baffle is not more than 80, the second separation baffle sets up the fourth opening is close to the top of gas outlet, first separation baffle with the second separation baffle all is provided with a plurality of gas perforating hole.
A second aspect of the present invention provides a method of preparing a silicon composite material, carried out in any of the above-described apparatus, comprising the steps of:
and placing the silicon-based material at the bottom of the reaction unit close to the gas inlet, inputting gas from the gas inlet into the reaction unit, carrying out cracking reaction on the gas entering the reaction unit, carrying out coating reaction on the gas and the fluidized silicon-based material, and obtaining the silicon composite material after the reaction is finished.
In a specific embodiment, the temperature of the reaction unit is 380-.
In one embodiment, the ratio of the vertical distance of the fragmentation unit from the gas inlet to the height of the static bed of the silicon-based material is not more than 2.5.
The preparation device and the preparation method provided by the invention can effectively improve the uniformity of the silicon material surface coating layer, improve the cycle performance and the rate capability of the lithium ion battery, and can be used for producing the silicon composite material.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a manufacturing apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural view of a crushing member according to an embodiment of the present invention;
FIG. 3 is a schematic structural view of a crushing member according to yet another embodiment of the present invention;
FIG. 4 is a side view of a crushing member according to an embodiment of the invention;
FIG. 5 is a schematic view of a crushing unit provided in accordance with an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a separating baffle according to an embodiment of the present invention;
fig. 7 is an expanded view of a first separating baffle according to an embodiment of the present invention;
fig. 8 is a plan view of a second separating baffle according to yet another embodiment of the present invention;
FIG. 9 is a scanning electron micrograph of a nitrogen-doped silicon-carbon composite prepared according to example 1 of the present invention;
FIG. 10 is a Raman spectrum of a nitrogen-doped silicon-carbon composite material prepared in example 1 of the present invention;
fig. 11 is a charge-discharge curve of the nitrogen-doped silicon-carbon composite material prepared in example 2 of the present invention.
Description of reference numerals:
1: gas inlet, 2: reaction unit, 3: crushing unit, 3-1: first crushing unit, 3-2: second crushing unit, 4: separation baffle, 4-1: first separation baffle, 4-2: second separation baffle, 5: cyclone, 6: gas outlet, 10: first lower baffle, 11: first upper baffle, 12: second lower baffle, 13: second upper baffle, 14: connecting plate, 15: lower via, 16: upper through hole, 17: and a flow guide pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The process of coating the silicon material by adopting a fluidized bed chemical vapor deposition method mainly comprises the following steps: the method comprises the steps of introducing gas to enable silicon material particles to be fluidized in a fluidized bed by adopting a fluidized bed reaction device, simultaneously, cracking the gas in the fluidized bed to obtain a simple substance, reacting the cracked simple substance with the fluidized silicon material particles and coating the fluidized silicon material particles on the surfaces of the silicon material particles to obtain the silicon composite material, for example, placing the silicon material in a fluidized bed reaction unit, introducing methane gas, pushing the silicon material to be fluidized by the methane gas, cracking the silicon material into a carbon simple substance on the one hand, reacting the carbon simple substance with the fluidized silicon material particles and coating the fluidized silicon material particles on the surfaces of the silicon material particles to obtain the silicon composite material coated with a carbon layer.
In the reaction process, silicon material particles are easy to agglomerate, reaction gas is easy to form bubbles when contacting with the agglomerates, the gas-solid contact efficiency is influenced, the coating effect of the silicon material particles is influenced, and the thickness controllability and uniformity of a coating layer are poor. The fluidized quality can be effectively improved by arranging the inner members in the fluidized bed reaction unit, the improvement effect of the inner members with different structures on the fluidized quality is different, the fluidization quality is further improved, and the improvement on the coating uniformity of the silicon material is one of the problems which are continuously concerned by the technical personnel in the field.
In order to solve the above technical problems, a first aspect of the present invention provides a preparation apparatus for a silicon composite material, which may be a fluidized bed, fig. 1 is a schematic structural diagram of the preparation apparatus according to an embodiment of the present invention, and as shown in fig. 1, the preparation apparatus includes a reaction unit 2, a gas inlet 1 disposed at the bottom of the reaction unit, and a gas outlet 6 disposed at the top of the reaction unit, the bottom of the reaction unit 2 near the gas inlet 1 is used for placing silicon materials, the gas inlet 1 is used for introducing gas, and the gas outlet 6 is used for discharging unreacted gas.
At least one crushing unit 3 is arranged in the reaction unit 2 and used for crushing and updating bubbles, so that the gas exchange amount between a bubble phase and an emulsion phase is increased, the gas-solid contact efficiency is increased, the coating of the silicon material is more uniform and controllable, and the cycle performance and the rate performance of the lithium ion battery are improved.
The crushing unit 3 comprises a number of crushing members arranged in parallel, in a specific embodiment, fig. 2 is a schematic structural view of a crushing member according to an embodiment of the invention, fig. 3 is a schematic structural view of a crushing member according to a further embodiment of the invention, fig. 4 is a side view of a crushing member according to an embodiment of the invention, as shown in fig. 2-4, the crushing member comprises a first baffle plate and a second baffle plate which are arranged oppositely and do not contact, the first baffle plate comprises a first upper baffle plate 11 and a first lower baffle plate 10 which are connected with each other, the second baffle plate comprises a second upper baffle plate 13 and a second lower baffle plate 12 which are connected with each other, the first upper baffle plate 11 and the second upper baffle plate 13 are arranged in parallel, the first lower baffle plate 10 and the second lower baffle plate 12 have an included angle of 15-90 °, i.e. the first upper baffle plate 11 and the second upper baffle plate 13 form a first opening towards the gas outlet 6, the first lower baffle 10 and the second lower baffle 12 form a second opening toward the gas inlet 1, and the area of the second opening is smaller than that of the first opening.
The first upper baffle 11 and the second upper baffle 13 are respectively provided with an upper through hole 16, the first lower baffle 10 and the second lower baffle 12 are respectively provided with a lower through hole 15, the upper through holes 16 and the lower through holes 15 are sequentially staggered, namely, in the vertical direction of the gas inlet 1 towards the gas outlet 6, the upper through holes 16 and the lower through holes 15 are not overlapped.
When the gas and fluidized solid mixture flows through the crushing unit 3, the gas and fluidized solid mixture passes through the flow guiding effect of the first lower baffle plate 10 and the second lower baffle plate 12, has a certain radial velocity component, strengthens radial diffusion of silicon material particles, is favorable for crushing entrained bubbles, and orderly compresses the bubbles entering the flow guiding pipe 17 under the synergistic action of the flow guiding pipe 17, a part of the gas and the silicon material particles are ejected from the lower through hole 15, a warm and high-quality gas-solid ejection phase is formed in a certain pressure resistance range, the bubbles in other gas-solid two phases outside the crushing unit 3 can be effectively crushed due to the large radial velocity of the ejected particles, the fluidization quality outside the crushing unit 3 is improved, the pressure resistance is not very large, and due to the pressure difference of the gas-solid two phases outside the crushing unit 3, a part of the gas and particles outside the crushing unit 3 are pumped into the crushing member through the upper through hole 16, and the gas and the silicon material particles between the draft tube 17 and the first baffle plate and the second baffle plate form a turbulent flow state, which is beneficial to improving the dispersion uniformity of the silicon material particles and improving the coating effect.
It is understood that the size of the bubbles in the reaction unit 2 is greatly related to the structure of the breaking member, and the present invention further defines the breaking member in order to further enhance the breaking effect of the bubbles, and specifically, the vertical distance a between the first upper baffle 11 and the second upper baffle 13 is 40 to 500mm, and the height b between the first upper baffle 11 and the second upper baffle 13 is 20 to 400 mm.
The ratio of the total area of the upper through holes 16 to the total area of the first upper baffle plate 11 and the second upper baffle plate 13 is not more than 10 percent, and is further 0.1 to 3 percent; the ratio of the total area of the lower through holes 15 to the total area of the first lower baffle plate 10 and the second lower baffle plate 12 is not more than 5%, and further 0.5% -5%, and the shapes of the upper through holes 16 and the lower through holes 15 can be oval and square as shown in fig. 2-3, and can also be reasonably arranged as required.
When the cross-sectional shape of the draft tube 17 is an inverted triangle as shown in fig. 2 or a circle as shown in fig. 3, the crushing effect on bubbles is better; in addition, in order to facilitate the heat transfer in the bed, the draft tube 17 can be a draft tube with heat exchange function.
The crushing members in different crushing units 3 are arranged in a staggered manner, and are suitable for being used when the gas velocity is high, fig. 5 is a schematic view of the crushing unit provided by an embodiment of the invention, as shown in fig. 5, a first crushing unit 3-1 and a second crushing unit 3-2 are sequentially arranged in a reaction unit 2 from a side close to a gas inlet 1 to a side close to a gas outlet 6, and an included angle between the crushing member in the first crushing unit 3-1 and the crushing member in the second crushing unit 3-2 is alpha, wherein alpha is more than 0 degrees and less than 180 degrees, and further alpha is 90 degrees.
The position of the crushing unit 3 in the reaction unit 2 is regulated, which is helpful for controlling the diameter of the bubbles in the reaction unit 2 and improving the transmission of gas and solid phases in the reaction unit 2, specifically, the vertical distance between the crushing unit 3 and the gas inlet 1 is not less than 100mm, and when the crushing unit 3 comprises the first crushing unit 3-1 and the second crushing unit 3-2, the vertical distance between the first crushing unit 3-1 close to the gas inlet 1 and the gas inlet 1 is not less than 100 mm.
Because the silicon material coating by the fluidized bed chemical vapor deposition method is characterized by larger bubbles and difficult gas-solid separation, a gas-solid separator is arranged at one side close to a gas outlet 6, the separation efficiency of a conventional gas-solid separator, such as a cyclone separator, is usually not higher than 99 percent, and escaped silicon material particles seriously affect the product yield and the economic benefit, therefore, the device also comprises a separation unit arranged at one side close to the gas outlet 6 of the crushing unit 3, the separation unit comprises a separation baffle plate 4 besides a conventional cyclone separator 5, and researches show that the escaped direction of the silicon material particles presents the distribution characteristics of four-circumference density and thin middle, therefore, as shown in figure 6, the separation baffle plate 4 provided by the invention is sequentially provided with a first separation baffle plate 4-1 and a second separation baffle plate 4-2 from one side far away from the gas outlet 6 to one side close to the gas outlet 1, the first separating baffle 4-1 is fan-shaped and encloses to form a third opening facing the gas inlet 1 and a fourth opening facing the gas outlet 6, the included angle beta between the plane of the third opening and the first separating baffle 4-1 is not more than 80 degrees, furthermore, the included angle beta between the plane of the third opening and the first separating baffle 4-1 is 15-30 degrees, the second separating baffle 4-2 is arranged above the fourth opening close to the gas outlet 6 and is parallel to the plane of the fourth opening, most of escaping particles are blocked from rising by the first separation baffle 4-1 with an inclined angle and returned to the reaction unit 2, a second separating baffle 4-2 is used to separate a portion of the particles flowing in the central region, through the combined design of the separation baffle 4 and the crushing unit 3, an integral high-efficiency nanoparticle fluidized bed reaction system is formed.
Each of the first separation baffle 4-1 and the second separation baffle 4-2 is provided with a plurality of gas passing holes for passing unreacted gas, fig. 7 is an expanded view of the first separation baffle provided in an embodiment of the present invention, and fig. 8 is a plan view of the second separation baffle provided in another embodiment of the present invention, as shown in fig. 7-8, the first separation baffle 4-1 has the square gas passing holes as shown in fig. 7, and the aperture ratio is 1% to 10%, that is, the total area of the gas passing holes is 1% to 10% of the total area of the first separation baffle 4-1; the second separation baffle 4-2 has square gas passing holes as shown in fig. 8, and the gas passing holes of the first separation baffle 4-1 and the second separation baffle 4-2 may have a circular shape, a corrugated shape, an umbrella shape, or the like, in addition to the square holes.
The ratio of the cross-sectional area of the second separating baffle 4-2 to the cross-sectional area of the first separating baffle 4-1 is 0.1 to 1, and the ratio of the cross-sectional area of the second separating baffle 4-2 to the cross-sectional area of the third opening is not less than 1, further 1.2 to 1.8.
The vertical distance between the second separating baffle 4-2 and the first separating baffle 4-1 is 10-500 mm.
The cyclone separator 5 may be conventional in the art and the present invention will not be described in detail herein.
A second aspect of the present invention provides a method of preparing a silicon composite material, carried out in any of the above apparatus, comprising the steps of:
the silicon material is placed at the bottom of a reaction unit 2 close to a gas inlet 1, gas is input from the gas inlet 1 and enters the reaction unit 2, the gas entering the reaction unit 2 is subjected to cracking reaction and pushes the silicon material to fluidize, bubbles formed by particle aggregates and the gas are gradually crushed by a crushing unit 3 to form a high-quality gas-solid flow state, high-quality fluidized silicon material particles react with a cracked simple substance and are coated on the surface of the silicon material to form a silicon composite material, unreacted gas is separated by a separation baffle 4 and a cyclone separator 5 and then flows out from a gas outlet 6, the particle substances return to the reaction unit 2 through the separation baffle 4 and the cyclone separator 5, and after the reaction is finished, the reactor is naturally cooled to room temperature and reaction products can be taken out.
In one embodiment, the reaction unit has a temperature of 380-.
The vertical distance between the crushing unit 3 and the gas inlet 1 is a, the height of the static bed of the silicon-based material is b, the vertical distance between the first separating baffle 4-1 and the gas inlet 1 is c, a: c is less than or equal to 2.5, b: c is 2.5-4.
The silicon material is pretreated silicon powder, the particle size of the silicon material is 0.01-50 microns, further 0.01-10 microns, the gas can be one or more of a carbon source, a nitrogen source, a sulfur source and an inert gas, specifically, the carbon source is one or more of methane, ethane, propane, ethylene, acetylene and propylene, the nitrogen source is one or more of acetonitrile, pyridine, pyrrole, ammonia gas and nitrogen dioxide, the sulfur source is one or more of hydrogen sulfide, thiophene and sulfur dioxide, and the inert gas is one or more of nitrogen, argon and helium.
The invention is illustrated in detail below with reference to specific examples:
example 1
In the present embodiment, the device shown in fig. 1 is adopted, 2 crushing units are provided, each crushing unit includes 4 crushing members, an included angle α between a crushing member in a first crushing unit and a crushing member in a second crushing unit is 90 °, the crushing members have the structure shown in fig. 2, and include a first upper baffle and a first lower baffle which are connected to each other, and a second upper baffle and a second lower baffle which are connected to each other, the first upper baffle and the second upper baffle are arranged in parallel, and the included angle between the first lower baffle and the second lower baffle is 60 °; the draft tube has a heat exchange function, and the ratio of the total area of the upper through holes 16 to the total area of the first upper baffle and the second upper baffle is 6%; the ratio of the total area of the lower through holes 15 to the total area of the first lower baffle and the second lower baffle is 3%. The vertical distance between the first upper baffle and the second upper baffle is 150 mm; the height of the first upper baffle plate and the second upper baffle plate is 200 mm. The first crusher unit is at a vertical distance of 200mm from the gas inlet 1. The gas through holes in the first separating baffle are square, and the gas through holes in the second separating baffle are umbrella-shaped.
The reaction temperature in the fluidized bed reaction device is 850 ℃, the reaction pressure (gauge pressure) is 0.01Mpa, the carbon source is a mixture of methane, ethylene and propylene, the nitrogen source and inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 80 nm.
When the silicon composite material prepared in this embodiment is observed by an electron microscope, as shown in fig. 9, the particle size of the silicon composite material provided in this embodiment is relatively uniform, which indicates that the degree of uniformity of the surface coating layer of the silicon material is relatively good. Fig. 10 is a raman spectrum of the nitrogen-doped silicon-carbon composite prepared in example 1 of the present invention, and as shown in fig. 10, the silicon composite has typical D and G peaks.
After the electrode performance of the silicon composite material prepared in the embodiment is measured by a charge and discharge tester, the capacity of the silicon composite material is 2315, 2021 and 1320mAh/g under the current density of 0.3, 0.5 and 1A/g respectively, and the capacity retention rate is 82% after the silicon composite material is circulated for 500 circles under the current density of 2A/g.
Example 2
The apparatus adopted in this embodiment can be referred to embodiment 1, except that: the ratio of the total area of the upper through holes to the total area of the first upper baffle plate and the second upper baffle plate is 8%; the ratio of the total area of the lower through holes to the total area of the first lower baffle and the second lower baffle is 2%. The vertical distance between the first upper baffle and the second upper baffle is 180 mm; the height of the first upper baffle and the second upper baffle is 180 mm.
The reaction temperature in the fluidized bed reaction device is 850 ℃, the reaction pressure (gauge pressure) is 0.02Mpa, the carbon source is a mixture of methane, ethylene and propylene, the nitrogen source and inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 100 nm.
The content of nitrogen doped in the silicon composite material is detected, and the content of nitrogen doped is 2.08 wt% through detection, which indicates that the nitrogen element is successfully doped into the silicon composite material. Fig. 11 is a charge-discharge curve of the nitrogen-doped silicon-carbon composite material prepared in example 2 of the present invention, and as shown in fig. 11, after the electrode performance of the silicon composite material prepared in this embodiment is measured by a charge-discharge tester, the capacities of the silicon composite material prepared in this embodiment are 2367, 2045, and 1386mAh/g at current densities of 0.3, 0.5, and 1A/g, respectively, and after 500 cycles at a current density of 2A/g, the capacity retention ratio is 85%, which shows good cycle characteristics.
Example 3
The apparatus adopted in this embodiment can be referred to embodiment 1, except that: the ratio of the total area of the upper through holes to the total area of the first upper baffle plate and the second upper baffle plate is 8%; the ratio of the total area of the lower through holes to the total area of the first lower baffle and the second lower baffle is 2%. The vertical distance between the first upper baffle and the second upper baffle is 180 mm; the height of the first upper baffle and the second upper baffle is 180 mm.
The reaction temperature in the fluidized bed reaction device is 650 ℃, the reaction pressure (gauge pressure) is 0.02Mpa, the carbon source is the mixture of ethylene and propylene, the sulfur source and inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 80 nm.
The sulfur content in the silicon composite material is detected, and the sulfur content is 2.35 wt% through detection. By the same method as that of the embodiment 2, after the electrode performance of the silicon composite material prepared in the embodiment is measured by a charge and discharge tester, the capacity of the silicon composite material is 2336, 2025 and 1372mAh/g at current densities of 0.3, 0.5 and 1A/g, and the capacity retention rate is 81.5% after the silicon composite material is circulated for 800 cycles at a current density of 2A/g.
Example 4
The apparatus adopted in this embodiment can be referred to embodiment 1, except that: the ratio of the total area of the upper through holes to the total area of the first upper baffle plate and the second upper baffle plate is 8%; the ratio of the total area of the lower through holes to the total area of the first lower baffle and the second lower baffle is 2%. The vertical distance between the first upper baffle and the second upper baffle is 180 mm; the height of the first upper baffle plate and the second upper baffle plate is 180 mm.
The reaction temperature in the fluidized bed reaction device is 850 ℃, the reaction pressure (gauge pressure) is 0.02Mpa, the carbon source is a mixture of methane, ethylene and propylene, the nitrogen source, the sulfur source and the inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 100 nm.
Detecting the sulfur content and the nitrogen content in the silicon composite material, wherein the sulfur content is 2.42 wt% and the nitrogen content is 2.38 wt%; by adopting the same method as that in example 2, after the electrode performance of the silicon composite material prepared in the present example is measured by a charge and discharge tester, the capacities are 2356, 2038 and 1379mAh/g at current densities of 0.3, 0.5 and 1A/g, respectively, and after the silicon composite material is circulated for 800 cycles at a current density of 2A/g, the capacity retention rate is 81%, so that excellent cycle characteristics are shown.
Comparative example 1
The comparative example employed a conventional fluidized bed reaction apparatus, and no crushing unit was provided. The reaction temperature in the fluidized bed reaction device is 850 ℃, the reaction pressure (gauge pressure) is 0.01Mpa, the carbon source is a mixture of methane, ethylene and propylene, the nitrogen source and inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 80 nm.
The capacities of the silicon composite materials obtained after the reaction were 1402, 1085 and 751mAh/g at current densities of 0.3, 0.5 and 1A/g, respectively, and the capacity retention rate was 45% after 500 cycles at a current density of 2A/g.
Comparative example 2
This comparative example employed a conventional fluidized bed reaction apparatus, provided with a conventional grid as a crushing member. The reaction temperature in the fluidized bed reaction device is 850 ℃, the reaction pressure (gauge pressure) is 0.01Mpa, the carbon source is a mixture of methane, ethylene and propylene, the nitrogen source and inert gas are simultaneously introduced, and the average grain diameter of the silicon-based material is 80 nm.
The capacities of the silicon composite materials obtained after the reaction are 1442, 1091 and 762mAh/g under the current densities of 0.3, 0.5 and 1A/g respectively, and the capacity retention rate is 46% after the silicon composite materials are circulated for 500 circles under the current density of 2A/g.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The preparation device of the silicon composite material is characterized by comprising a reaction unit, a gas inlet arranged at the bottom of the reaction unit and a gas outlet arranged at the top of the reaction unit;
at least one crushing unit is arranged in the reaction unit, and the crushing unit comprises a plurality of crushing members which are arranged in parallel;
the crushing member comprises a first baffle, a second baffle and a flow guide pipe, the first baffle and the second baffle are oppositely arranged and form a first opening and a second opening which are mutually communicated, the first opening faces the gas outlet, the second opening faces the gas inlet, and the first baffle and the second baffle are provided with a plurality of through holes; the honeycomb duct is located between the first baffle and the second baffle, and the setting direction of the honeycomb duct is perpendicular to the direction of the gas inlet towards the gas outlet.
2. The apparatus of claim 1, wherein the reaction unit is provided with a first crushing unit and a second crushing unit in sequence from the side close to the gas inlet to the side close to the gas outlet, the included angle between the crushing members in the first crushing unit and the crushing members in the second crushing unit is alpha, and the included angle is more than 0 degrees and less than 180 degrees.
3. The device according to claim 1 or 2, wherein the first baffle comprises a first upper baffle and a first lower baffle which are connected with each other, the second baffle comprises a second upper baffle and a second lower baffle which are connected with each other, the first upper baffle and the second upper baffle are arranged in parallel, and the included angle between the first lower baffle and the second lower baffle is 15-90 degrees;
the first upper baffle and the second upper baffle are respectively provided with an upper through hole, the first lower baffle and the second lower baffle are respectively provided with a lower through hole, and the upper through holes and the lower through holes are sequentially staggered.
4. The apparatus of claim 3, wherein the ratio of the total area of the upper through holes to the total area of the first and second upper baffles is no greater than 10%; the ratio of the total area of the lower through holes to the total area of the first lower baffle and the second lower baffle is not more than 5%.
5. The apparatus of claim 3, wherein the vertical spacing between the first and second upper baffles is 40-500 mm; the height of the first upper baffle and the second upper baffle is 20-400 mm.
6. The apparatus of claim 1, wherein the vertical distance of the breaking unit from the gas inlet is no less than 100 mm.
7. The device of claim 1, further comprising a separation unit arranged on one side of the crushing unit close to the gas outlet, wherein the separation unit comprises a first separation baffle close to one side of the gas inlet and a second separation baffle close to one side of the gas outlet, the first separation baffle surrounds and forms a third opening facing the gas inlet and a fourth opening facing the gas outlet, an included angle between a plane where the third opening is located and the first separation baffle is not more than 80 degrees, the second separation baffle is arranged above the fourth opening close to the gas outlet, and the first separation baffle and the second separation baffle are both provided with a plurality of gas through holes.
8. A method for the preparation of a silicon composite material, carried out in the apparatus of any one of claims 1 to 7, comprising the steps of:
and placing the silicon-based material at the bottom of the reaction unit close to the gas inlet, inputting gas from the gas inlet, allowing the gas to enter the reaction unit, carrying out cracking reaction on the gas entering the reaction unit, carrying out coating reaction on the gas and the fluidized silicon-based material, and obtaining the silicon composite material after the reaction is finished.
9. The method as claimed in claim 8, wherein the temperature of the reaction unit is 380-1000 ℃, the gauge pressure is 0.01-1Mpa, the time is 1-100min, and the superficial gas velocity is 0.001-1 m/s.
10. A method according to claim 8 or 9, wherein the ratio of the vertical distance of the breaking unit from the gas inlet to the height of the static bed of the silicon-based material is not more than 2.5.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85100040A (en) * | 1985-04-01 | 1986-07-16 | 清华大学 | Composite internals of fluidized bed reactors |
| CN202823324U (en) * | 2012-09-10 | 2013-03-27 | 中国科学院大连化学物理研究所 | Fluidized bed reactor for producing pyridine base |
| US20170151544A1 (en) * | 2015-12-01 | 2017-06-01 | Dow Global Technologies Llc | Fluidized Catalyst Stripping Unit for Displacing Entrained Gas From Catalyst Particles |
| CN109119627A (en) * | 2018-08-28 | 2019-01-01 | 中南大学 | A kind of preparation method and device of high performance silicon carbon based negative electrodes material |
| CN111056949A (en) * | 2018-10-17 | 2020-04-24 | 中国石油化工股份有限公司 | Reaction device and reaction method for preparing aniline through continuous reaction, regeneration and activation |
| CN111111562A (en) * | 2018-10-30 | 2020-05-08 | 中国石油化工股份有限公司 | Aromatic ammoxidation combined fluidized bed reaction device and reaction method thereof |
| CN111298727A (en) * | 2020-03-26 | 2020-06-19 | 中国石油化工股份有限公司 | Fluidized bed reaction device and fluidized reaction method for nitrobenzene hydrogenation |
| US20210130947A1 (en) * | 2015-04-12 | 2021-05-06 | Clb Americas, Inc. | Composite formed from semi-continuous and multi-step process |
| CN213913681U (en) * | 2020-09-10 | 2021-08-10 | 西北大学 | Multistage fluidized bed reactor |
| US20210371371A1 (en) * | 2018-10-17 | 2021-12-02 | China Petroleum & Chemical Corporation | Double-trapezoid structural member, fluidized apparatus and nitro compound hydrogenation reaction process |
-
2022
- 2022-03-28 CN CN202210309172.1A patent/CN114649496B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85100040A (en) * | 1985-04-01 | 1986-07-16 | 清华大学 | Composite internals of fluidized bed reactors |
| CN202823324U (en) * | 2012-09-10 | 2013-03-27 | 中国科学院大连化学物理研究所 | Fluidized bed reactor for producing pyridine base |
| US20210130947A1 (en) * | 2015-04-12 | 2021-05-06 | Clb Americas, Inc. | Composite formed from semi-continuous and multi-step process |
| US20170151544A1 (en) * | 2015-12-01 | 2017-06-01 | Dow Global Technologies Llc | Fluidized Catalyst Stripping Unit for Displacing Entrained Gas From Catalyst Particles |
| CN109119627A (en) * | 2018-08-28 | 2019-01-01 | 中南大学 | A kind of preparation method and device of high performance silicon carbon based negative electrodes material |
| CN111056949A (en) * | 2018-10-17 | 2020-04-24 | 中国石油化工股份有限公司 | Reaction device and reaction method for preparing aniline through continuous reaction, regeneration and activation |
| US20210371371A1 (en) * | 2018-10-17 | 2021-12-02 | China Petroleum & Chemical Corporation | Double-trapezoid structural member, fluidized apparatus and nitro compound hydrogenation reaction process |
| CN111111562A (en) * | 2018-10-30 | 2020-05-08 | 中国石油化工股份有限公司 | Aromatic ammoxidation combined fluidized bed reaction device and reaction method thereof |
| CN111298727A (en) * | 2020-03-26 | 2020-06-19 | 中国石油化工股份有限公司 | Fluidized bed reaction device and fluidized reaction method for nitrobenzene hydrogenation |
| CN213913681U (en) * | 2020-09-10 | 2021-08-10 | 西北大学 | Multistage fluidized bed reactor |
Non-Patent Citations (1)
| Title |
|---|
| 刘对平;董芳芳;王蒙;魏庆;张永民;: "不同颗粒流化床层中挡板受力特性对比", 化工学报, no. 08 * |
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