CN111755682A - Silicon-carbon negative electrode material and preparation method thereof - Google Patents
Silicon-carbon negative electrode material and preparation method thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a silicon-carbon negative electrode material and a preparation method thereof, wherein the silicon-carbon negative electrode material comprises nano silicon, an oxide layer on the surface of the nano silicon and carbon; the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are (10-30): 100, respectively; the raw material of nano silicon is silicon source gas, the silicon source gas is solid silicon formed by decomposition in an inert atmosphere, the solid silicon is an aggregate of the nano silicon, and the aggregate is ground by a wet method, on one hand, the aggregate of the nano silicon is scattered and uniformly dispersed in slurry, and simultaneously, the granularity and the grain size of the nano silicon are further reduced, on the other hand, an oxide layer is formed on the surface of the nano silicon by the wet grinding, so that the surface activity of the nano silicon is reduced, and the cycle performance of the silicon-carbon negative electrode material can be obviously improved.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a silicon-carbon negative electrode material and a preparation method thereof.
Background
At present, the conventional lithium ion negative electrode material mainly adopts a graphite negative electrode, but the theoretical specific capacity of the graphite negative electrode is only 372mAh/g, and the urgent needs of users cannot be met. The theoretical capacity of silicon is up to 4200mAh/g, which is more than 10 times of the capacity of a graphite cathode material, and simultaneously, the coulomb efficiency of the silicon-carbon composite product is close to that of the graphite cathode, and the silicon-carbon composite product is low in price, environment-friendly, rich in earth reserves, and is the optimal choice of a new generation of high-capacity cathode material. However, since the silicon material has poor conductivity and the volume expansion of silicon reaches up to 300% during charging, the volume expansion during charging and discharging easily causes the collapse of the material structure and the peeling and pulverization of the electrode, resulting in the loss of the active material, further causing the sharp reduction of the battery capacity and the serious deterioration of the cycle performance.
In order to stabilize the structure of silicon in the charging and discharging process, relieve the expansion and achieve the effect of improving the electrochemical performance, a carbon material with high conductivity and high specific surface area is urgently needed, and the carbon material is mixed with silicon to be used as a lithium battery negative electrode material.
Disclosure of Invention
In order to solve the problems of the silicon-carbon cathode material, the invention provides a silicon-carbon cathode material and a preparation method thereof, the silicon-carbon cathode material comprises nano silicon, an oxide layer on the surface of the nano silicon and carbon, the raw material of the nano silicon is silicon source gas, the silicon source gas is decomposed into solid silicon in inert atmosphere, the solid silicon is an aggregate of the nano silicon, the aggregate is ground by a wet method, on one hand, the aggregate of the nano silicon is scattered and uniformly dispersed in slurry, and simultaneously, the granularity and the grain size of the nano silicon are further reduced, on the other hand, the oxide layer is formed on the surface of the nano silicon by the wet grinding, the surface activity of the nano silicon is reduced, so that accidents such as spontaneous combustion or explosion and the like after the dry powder of the nano silicon contacts air are prevented, and simultaneously, the oxide layer is formed on the surface of the nano silicon, which is beneficial to inhibiting the volume expansion effect of, the cycle performance of the silicon-carbon cathode material can be obviously improved.
Because silicon is a semiconductor and has poor conductivity performance, the prepared nano silicon is combined with a carbon material, so that the conductivity and the lithium ion diffusion rate of the negative electrode material can be improved, meanwhile, because certain volume expansion of silicon inevitably occurs in the charging and discharging processes, a formed SEI film is cracked and reconstructed, and the irreversible loss of lithium ions is large, so that the cycle performance of the negative electrode material is influenced, and the composite carbon material can form a protective shell around the nano silicon to isolate the erosion of electrode liquid, so that the comprehensive electrochemical performance of the negative electrode material is improved.
More specifically, the invention discloses a silicon-carbon negative electrode material, which is characterized in that: the silicon-carbon cathode material comprises nano silicon, an oxide layer on the surface of the nano silicon and carbon.
Preferably, the mass proportion of the oxygen content of the surface of the nano silicon to the nano silicon is (5-30): 100, preferably (12-28): 100.
preferably, the oxide layer on the surface of the nano silicon exists in at least one of silicon oxide, OH < - > or free state of oxygen.
Preferably, the nano silicon is detected by a Mastersizer 3000 particle size analyzer, wherein the median particle size D50 is below 90nm, and the maximum particle size D100 is below 300 nm; the crystal grain of the nano silicon is calculated to be 10nm or less by the Scherrer equation based on the half-value width value of the diffraction peak attributed to Si (111) in the vicinity of 28.4 ° 2 θ by X-ray diffraction pattern analysis.
Preferably, the nano silicon has a concentration of 1.2-2.6 g/cm3True density of 2 to 100m2Specific surface area in g.
Preferably, the carbon content is 10 to 70 wt.%, preferably 30 to 50 wt.%, based on the total weight of the anode material.
Preferably, the carbon is one or a combination of amorphous carbon and crystalline carbon.
Preferably, the amorphous carbon comprises carbon formed by pyrolysis of a gas-phase carbon source and residual carbon formed by high-temperature calcination of a solid-phase carbon source, the high-temperature reaction is carried out in an inert atmosphere, and the gas-phase carbon source comprises one of methane, ethane, acetylene, natural gas, propylene, acetone and liquefied petroleum gas; the solid-phase carbon source comprises one of glucose, sucrose, natural asphalt, coal tar asphalt, petroleum asphalt, epoxy resin, phenolic resin, furfural resin, acrylic resin, formaldehyde resin and citric acid; the crystalline carbon includes artificial graphite and natural graphite; the high temperature is 600-900 ℃.
The invention also relates to a method for preparing the silicon-carbon negative electrode material, which is characterized by comprising the following steps:
(1) preparing nano silicon aggregate: introducing high-purity inert gas into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 600-900 ℃, and introducing silicon source gas for chemical vapor deposition at the flow rate of 1-5L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: adding nano-silicon aggregates into an organic solvent, wherein the solid content of a mixed solution is 10-40%, introducing the mixed slurry into a sand mill, wherein the diameter of grinding beads is 0.05-0.2 mm, the grinding time is 20-50h, obtaining the required nano-silicon slurry, and drying the nano-silicon slurry to obtain dry powder, wherein the oxygen content of the surface of the nano-silicon and the mass proportion of the nano-silicon are (5-30): 100, preferably (12-28): 100, respectively;
(3) preparing a silicon-carbon negative electrode material: uniformly stirring the nano silicon dry powder prepared in the step (2) and carbon, drying and carbonizing, and controlling the mass ratio of the carbon to be 10-70 wt% (preferably 30-50 wt%), so as to obtain a silicon-carbon negative electrode material;
the silicon source gas in the step (1) is one or the combination of more than two of silane, dichlorosilane, trichlorosilane, silicon tetrachloride and silicon tetrafluoride; the inert gas is one of nitrogen, helium, neon and argon;
the organic solvent in the step (2) is one or more of methanol, toluene, benzyl alcohol, ethanol, ethylene glycol, chlorinated ethanol, propanol, isopropanol, propylene glycol, butanol, n-butanol, isobutanol, pentanol, neopentyl alcohol, octanol, acetone or cyclohexanone;
the material of the grinding beads in the step (2) is one of hard alloy, zirconia and stainless steel;
the carbon in the step (3) is one or the combination of amorphous carbon and crystalline carbon;
the amorphous carbon comprises carbon formed by high-temperature decomposition of a gas-phase carbon source and residual carbon formed by high-temperature calcination of a solid-phase carbon source, high-temperature reactions are carried out in an inert atmosphere at the high temperature of 600-900 ℃, and the gas-phase carbon source comprises one of methane, ethane, acetylene, natural gas, propylene, acetone and liquefied petroleum gas;
the solid-phase carbon source comprises one of glucose, sucrose, natural asphalt, coal tar asphalt, petroleum asphalt, epoxy resin, phenolic resin, furfural resin, acrylic resin, formaldehyde resin and citric acid;
the crystalline carbon includes artificial graphite and natural graphite.
Preferably, the grinding in step (2) is wet grinding, the wet grinding is carried out in air, and the grinding equipment is a sand mill.
The invention also relates to a lithium ion battery cathode material which is characterized by being any one of the silicon-carbon cathode materials.
Compared with the prior art, the invention has the advantages that:
(1) according to the silicon-carbon cathode material prepared by the invention, the silicon source gas is decomposed in the inert atmosphere to form the nano-silicon aggregate, so that the absolute volume expansion of silicon is reduced, and the dynamics of nano-silicon in the cathode material is improved;
(2) the silicon-carbon negative electrode material prepared by the invention is ground by a wet method, aggregates of nano-silicon are scattered and uniformly dispersed in slurry, more importantly, a layer of oxide is formed on the surface of the nano-silicon by the wet grinding, so that the surface activity of the nano-silicon is reduced, accidents such as spontaneous combustion or explosion and the like after the dry nano-silicon powder contacts air are prevented, meanwhile, the oxide formed on the surface of the nano-silicon is beneficial to inhibiting the expansion effect of the silicon-carbon negative electrode material in the charging and discharging processes, and the silicon-carbon negative electrode material has more excellent electrochemical performance;
(3) according to the silicon-carbon cathode material prepared by the invention, the prepared nano silicon is combined with the carbon material, so that the conductivity and the lithium ion diffusion rate of the cathode material can be improved, meanwhile, the formed SEI film is cracked and reconstructed due to inevitable certain volume expansion of silicon in the charging and discharging processes, the irreversible loss of lithium ions is large, the cycle performance of the cathode material is influenced, and the composite carbon material can form a protective shell around the nano silicon to isolate the erosion of electrode liquid, so that the comprehensive electrochemical performance of the cathode material is improved;
(4) the silicon-carbon anode material prepared by the invention has excellent electrochemical performance, high specific capacity (more than 2000mAh/g), high first efficiency (more than 81%), and excellent cycle performance (18650 cylindrical battery &450 capacity, 500-cycle retention rate > 89/%).
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is an SEM image of nano-silicon prepared in example 1 of the present invention.
Fig. 2 is an XRD pattern of nano-silicon prepared in example 1 of the present invention.
Fig. 3 is a first charge-discharge curve of the button cell prepared in example 1 of the present invention.
FIG. 4 is a cycle curve at 1C/1C rate for a 18650 cylindrical cell made according to example 1 of the invention.
Detailed Description
For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
A preparation method of a silicon-carbon negative electrode material for a lithium ion battery comprises the following steps:
(1) preparing nano silicon aggregate: introducing high-purity nitrogen into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 800 ℃ at the heating rate of 2 ℃/min, and introducing trichlorosilane gas for chemical vapor deposition at the flow rate of 1L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: adding 1000g of nano-silicon aggregate into ethanol, wherein the solid content of the mixed solution is 10%, introducing the mixed slurry into a sand mill, wherein the grinding beads are made of zirconium oxide, the diameter of the grinding beads is 0.05mm, the grinding time is 20h, obtaining the required nano-silicon slurry, and drying the nano-silicon slurry to obtain dry powder. The median particle size of the nano silicon obtained by testing is 69nm, the maximum particle size D100 is 138nm, the crystal grain of the nano silicon is 7.1nm, and the mass proportion of the oxygen content on the surface of the nano silicon to the nano silicon is 13: 100, respectively;
(3) preparing a silicon-carbon negative electrode material: and (3) placing the dry powder in the step (2) in a vapor deposition furnace, introducing nitrogen to remove air until the oxygen content is lower than 100ppm, then heating to 800 ℃ at the heating rate of 3 ℃/min, introducing acetylene to carry out vapor deposition, wherein the flow is 1L/min, compounding carbon decomposed by the acetylene and the nano silicon dry powder, and controlling the carbon content of the vapor deposition to be 10 wt% to obtain the silicon-carbon cathode material.
Example 2
(1) Preparing nano silicon aggregate: introducing high-purity nitrogen into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 600 ℃ at the heating rate of 2 ℃/min, and introducing silicon tetrachloride gas for chemical vapor deposition at the flow rate of 2L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: adding 1000g of the nano silicon aggregate in the step (1) into propanol, wherein the solid content of the mixed solution is 20%, and introducing the mixed slurry into a sand mill, wherein the grinding beads are made of zirconium oxide, the diameter of the grinding beads is 0.1mm, and the grinding time is 30h, so as to obtain the required nano silicon slurry. The median particle size of the nano silicon obtained by testing is 74nm, the maximum particle size D100 is 184nm, the crystal grain of the nano silicon is 7.9nm, the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are 18: 100, respectively;
(3) preparing a silicon-carbon negative electrode material: adding phenolic resin into the nano silicon slurry obtained in the step (2), uniformly stirring, drying, placing in a box furnace, introducing nitrogen to remove air until the oxygen content is lower than 100ppm, heating to 600 ℃ at a heating speed of 3 ℃/min, keeping the temperature for 2h, and controlling the content of cracked carbon in the phenolic resin to be 10 wt.% to obtain the silicon-carbon cathode material.
Example 3
(1) Preparing nano silicon aggregate: introducing high-purity nitrogen into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 900 ℃ at the heating rate of 2 ℃/min, and introducing silicon tetrafluoride gas for chemical vapor deposition at the flow rate of 3L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: adding 1000g of the nano silicon aggregate in the step (1) into butanol, wherein the solid content of the mixed solution is 30%, and introducing the mixed slurry into a sand mill, wherein the grinding beads are made of hard alloy, the diameter of the grinding beads is 0.2mm, and the grinding time is 40h, so as to obtain the required nano silicon slurry. The median particle diameter of the nano silicon is 81nm, the maximum particle size D100 is 237nm, the crystal grain of the nano silicon is 8.3nm, and the mass proportion of the oxygen content on the surface of the nano silicon to the nano silicon is 19: 100, respectively;
(3) preparing a silicon-carbon negative electrode material: adding artificial graphite into the nano silicon slurry obtained in the step (2), uniformly stirring, drying, placing in a box furnace, introducing nitrogen to remove air until the oxygen content is lower than 100ppm, heating to 700 ℃ at a heating speed of 3 ℃/min, keeping the temperature for 2h, controlling the content of the artificial graphite to be 10 wt.%, and drying to obtain the silicon-carbon cathode material.
Example 4
(1) Preparing nano silicon aggregate: introducing high-purity nitrogen into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 700 ℃ at the heating rate of 2 ℃/min, and introducing silicon tetrafluoride gas for chemical vapor deposition at the flow rate of 5L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: and (2) adding 1000g of the nano silicon aggregate in the step (1) into pentanol, wherein the solid content of the mixed solution is 40%, and introducing the mixed slurry into a sand mill, wherein the grinding beads are made of stainless steel, the diameter of the grinding beads is 0.5mm, and the grinding time is 50h, so as to obtain the required nano silicon slurry. The median particle size of the nano silicon obtained by testing is 88nm, the maximum particle size D100 is 276nm, the crystal grain of the nano silicon is 9.5nm, and the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are 28: 100, respectively;
(3) preparing a silicon-carbon negative electrode material: adding phenolic resin and artificial graphite into the nano silicon slurry obtained in the step (2), uniformly stirring, drying, then placing in a box furnace, introducing nitrogen to remove air until the oxygen content is lower than 100ppm, then heating to 900 ℃ at a heating speed of 3 ℃/min, keeping the temperature for 2h, and controlling the total content of the cracked carbon of the phenolic resin and the artificial graphite to be 10 wt% to obtain the silicon-carbon cathode material.
Example 5
Step (1) and step (2) are the same as example 1, and the carbon content of vapor deposition is controlled to be 30 wt.% in step (3) by increasing the flow rate and deposition time of acetylene, so as to obtain the silicon-carbon anode material.
Example 6
Step (1) and step (2) are the same as example 1, and the carbon content of vapor deposition is controlled to be 50 wt.% in step (3) by increasing the flow rate and deposition time of acetylene, so as to obtain the silicon-carbon anode material.
Example 7
Step (1) and step (2) are the same as example 1, and the carbon content of vapor deposition is controlled to be 70 wt.% in step (3) by increasing the flow rate and deposition time of acetylene, so as to obtain the silicon-carbon anode material.
Comparative example 1
The difference from example 1 is that step (1) is not performed, i.e., the silicon raw material is not obtained by gas phase silicon decomposition, but is micron-sized silicon particles, and the rest is the same as example 1, and will not be described herein again.
Comparative example 2
The difference from example 1 is that step (2) is not performed, i.e., the silicon agglomerates are not subjected to the wet milling process, and the rest is the same as example 1, which is not described herein again.
Comparative example 3
The difference from the embodiment 1 is that the step (3) is not performed, that is, no carbon is added to the silicon-carbon anode material, and the rest is the same as the embodiment 1, and the description is omitted here.
Comparative example 4
The difference from example 1 is that step (2), i.e., the wet grinding time of the silicon agglomerates is 2h, which is the same as example 1 and will not be described again.
The test shows that the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are 3: 100.
comparative example 5
The difference from example 1 is that step (2), i.e., the wet grinding time of the silicon agglomerates is 65 hours, which is the same as example 1 and will not be described herein.
The test shows that the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are 41: 100.
the silicon carbon anode materials in examples 1 to 7 and comparative examples 1 to 5 were tested using the following methods:
the material particle size range was tested using a malvern laser particle sizer Mastersizer 3000.
The morphology and the graphical processing of the material were analyzed using a field emission Scanning Electron Microscope (SEM) (JSM-7160).
The oxygen content in the material is accurately and rapidly determined by adopting an oxygen nitrogen hydrogen analyzer (ONH).
The material is subjected to phase analysis by an XRD diffractometer (X' Pert3Powder), and the grain size of the material is determined.
The specific surface area of the negative electrode material was measured using a U.S. Mach Chart and pore Analyzer (TriStar II 3020).
The tap density of the negative electrode material was measured using a tap density analyzer (Congta Autotap single station).
The powder was tested for true density using an american mack true densitometer (AccuPyc II 1340).
The nano silicon of the embodiments 1 to 7 is detected to have 1.2 to 2.6g/cm3True density of 2 to 100m2Specific surface area in g.
Mixing the silicon-carbon negative electrode materials obtained in the examples 1 to 7 and the comparative examples 1 to 5 in pure water of a solvent according to the mass ratio of 91:2:2:5, homogenizing, controlling the solid content to be 45%, coating the mixture on a copper foil current collector, and drying in vacuum to obtain a negative electrode piece. Button cells were assembled in an argon atmosphere glove box using a separator Celgard2400, an electrolyte of 1mol/L LiPF6/EC + DMC + EMC (v/v 1:1:1), and a metallic lithium plate as the counter electrode. And (3) performing charge and discharge tests on the button cell, wherein the voltage interval is 5 mV-1.5V, and the current density is 80 mA/g. The first reversible capacity and efficiency of the silicon carbon anode materials in the examples and comparative examples were measured.
According to the first reversible capacity measured in the button cell, the silicon-containing negative electrode materials in the examples and the comparative examples are mixed with the same stable artificial graphite, and the first reversible capacity tested by the button cell of the mixed powder is 450 +/-2 mAh/g. And preparing a negative pole piece from the mixed powder by a button cell process, and assembling a 18650 cylindrical single cell by using a ternary pole piece prepared by a mature process as a positive pole, an isolating film and electrode liquid unchanged. The 18650 cylindrical single battery is subjected to charge and discharge tests, the voltage interval is 2.5 mV-4.2V, and the current density is 450 mA/g.
The test equipment of the button cell and the 18650 cylindrical single cell are both the LAND battery test system of Wuhanjinnuo electronics, Inc.
The performance test results of the silicon-carbon negative electrode materials of the examples and the comparative examples are shown in Table 1:
table 1 results of performance test of silicon carbon anode materials in examples 1 to 7 and comparative examples 1 to 5
As can be seen from table 1, the silicon-carbon negative electrode material prepared by the method of the present application can adjust the grain size of the obtained nano silicon by vapor silicon source deposition and wet grinding processes, wherein the median particle size D50 is below 90nm, and the maximum particle size D100 is below 300 nm; the crystal grain of the nano silicon is calculated to be 10nm or less by the Scherrer equation based on the half-value width value of the diffraction peak attributed to Si (111) in the vicinity of 28.4 ° 2 θ by X-ray diffraction pattern analysis. The prepared silicon-carbon cathode material has excellent cycle performance, 18650 cylindrical batteries and 450 capacity, and 500-cycle retention rate is more than 89/%. In examples 1 to 4, with the increasing of the nano-silicon median particle diameter D50 and the silicon crystal grains, the first reversible capacity of the obtained anode material gradually increases, the first coulombic efficiency gradually increases, but the cycle performance is obviously reduced. In examples 5 to 7, the first reversible capacity of the obtained negative electrode material gradually decreased with the gradual increase of the carbon content, but the first coulombic efficiency gradually increased, and the cycle performance of the battery was slightly improved.
In the comparative example 1, the silicon raw material of the silicon-carbon negative electrode material is not obtained by decomposing gas-phase silicon, but is micron-sized silicon particles, and the first reversible capacity, the first efficiency and the cycle performance of the prepared silicon-carbon negative electrode material are reduced; in the comparative example 2, the silicon aggregate is not subjected to the wet grinding process, but is directly compounded with the carbon material, local aggregation of nano silicon is formed inside the negative electrode material, so that the cycle performance is obviously reduced; in comparative example 3, when no carbon was added to the silicon-carbon negative electrode material, the conductivity of the silicon-carbon negative electrode material was deteriorated and side reactions with the electrolyte were increased, resulting in a significant decrease in the first coulombic efficiency and cycle performance. In comparative example 4, the wet grinding time of the silicon agglomerates was reduced to 2 hours, and the oxygen content on the surface of the nano silicon and the mass specific gravity of the nano silicon were 3: 100, the oxygen content is lower, the capacity of the obtained cathode material is slightly exerted, but the cycle performance of the battery is obviously deteriorated. In comparative example 5, the wet grinding time of the silicon agglomerates was extended to 65 hours, and the oxygen content on the surface of the silicon nanoparticles to the mass ratio of silicon nanoparticles was 41: 100, the oxygen content is significantly higher than that of the examples, the first reversible capacity exertion of the obtained negative electrode material is poor, and active lithium ions are continuously consumed in the battery charging and discharging process due to the excessively high oxygen content, thereby causing the deterioration of the cycle performance.
The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. A silicon-carbon negative electrode material is characterized in that: the silicon-carbon negative electrode material comprises nano silicon, an oxide layer on the surface of the nano silicon and carbon; the oxygen content of the surface of the nano silicon and the mass proportion of the nano silicon are (10-30): 100, preferably (12-28): 100.
2. the silicon-carbon anode material as claimed in claim 1, wherein the oxide layer on the surface of the nano silicon exists in at least one of silicon oxide, OH-or free oxygen.
3. The silicon-carbon anode material as claimed in claim 1, wherein the nano silicon is detected by a Mastersizer 300 particle size analyzer, wherein the median particle size D50 is below 90nm, and the maximum particle size D100 is below 300 nm; the crystal grain of the nano silicon is calculated to be 10nm or less by the Scherrer equation based on the half-value width value of the diffraction peak attributed to Si (111) in the vicinity of 28.4 ° 2 θ by X-ray diffraction pattern analysis.
4. The silicon-carbon anode material as claimed in claim 1, wherein the nano-silicon has a density of 1.2-2.6 g/cm3True density of 2 to 100m2Specific surface area in g.
5. Silicon-carbon anode material according to claim 1, wherein the carbon content is 10 to 70 wt.%, preferably 30 to 50 wt.%, based on the total weight of the anode material.
6. The silicon-carbon anode material as claimed in claim 1, wherein the carbon is one or a combination of amorphous carbon and crystalline carbon.
7. The silicon-carbon anode material of claim 1, wherein the amorphous carbon comprises carbon formed by pyrolysis of a gas-phase carbon source and residual carbon formed by high-temperature calcination of a solid-phase carbon source, the high-temperature reaction is performed in an inert atmosphere, and the gas-phase carbon source comprises one of methane, ethane, acetylene, natural gas, propylene, acetone and liquefied petroleum gas; the solid-phase carbon source comprises one of glucose, sucrose, natural asphalt, coal tar asphalt, petroleum asphalt, epoxy resin, phenolic resin, furfural resin, acrylic resin, formaldehyde resin and citric acid; the crystalline carbon includes artificial graphite and natural graphite; the high temperature is 600-900 ℃.
8. A method for preparing the silicon-carbon anode material according to any one of claims 1 to 7, comprising:
(1) preparing nano silicon aggregate: introducing high-purity inert gas into a vapor deposition furnace until the oxygen content in the furnace is lower than 100ppm, heating to 600-900 ℃, and introducing silicon source gas for chemical vapor deposition at the flow rate of 1-5L/min to obtain nano silicon aggregates;
(2) preparing nano silicon dry powder: adding nano-silicon aggregates into an organic solvent, wherein the solid content of a mixed solution is 10-40%, introducing the mixed slurry into a sand mill, wherein the diameter of grinding beads is 0.05-0.2 mm, the grinding time is 20-50h, obtaining the required nano-silicon slurry, and drying the nano-silicon slurry to obtain dry powder, wherein the oxygen content of the surface of the nano-silicon and the mass proportion of the nano-silicon are (5-30): 100, preferably (12-28): 100, respectively;
(3) preparing a silicon-carbon negative electrode material: uniformly stirring the nano silicon dry powder prepared in the step (2) and carbon, drying and carbonizing, and controlling the mass ratio of the carbon to be 10-70 wt% to obtain a silicon-carbon cathode material;
the silicon source gas in the step (1) is one or the combination of more than two of silane, dichlorosilane, trichlorosilane, silicon tetrachloride and silicon tetrafluoride; the inert gas is one of nitrogen, helium, neon and argon;
the organic solvent in the step (2) is one or more of methanol, toluene, benzyl alcohol, ethanol, ethylene glycol, chlorinated ethanol, propanol, isopropanol, propylene glycol, butanol, n-butanol, isobutanol, pentanol, neopentyl alcohol, octanol, acetone or cyclohexanone;
the material of the grinding beads in the step (2) is one of hard alloy, zirconia and stainless steel;
the carbon in the step (3) is one or the combination of amorphous carbon and crystalline carbon;
the amorphous carbon comprises carbon formed by high-temperature decomposition of a gas-phase carbon source and residual carbon formed by high-temperature calcination of a solid-phase carbon source, high-temperature reactions are carried out in an inert atmosphere at the high temperature of 600-900 ℃, and the gas-phase carbon source comprises one of methane, ethane, acetylene, natural gas, propylene, acetone and liquefied petroleum gas;
the solid-phase carbon source comprises one of glucose, sucrose, natural asphalt, coal tar asphalt, petroleum asphalt, epoxy resin, phenolic resin, furfural resin, acrylic resin, formaldehyde resin and citric acid;
the crystalline carbon includes artificial graphite and natural graphite.
9. The method for preparing the silicon-carbon anode material as claimed in claim 8, wherein the grinding in the step (2) is wet grinding, the wet grinding is carried out in air, and the grinding equipment is a sand mill.
10. A lithium ion battery negative electrode material, characterized in that the lithium ion battery negative electrode material is the silicon-carbon negative electrode material according to any one of claims 1 to 7.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104282894A (en) * | 2013-07-08 | 2015-01-14 | 北京化工大学 | Preparation method of porous Si/C composite microsphere |
| CN104638237A (en) * | 2015-01-20 | 2015-05-20 | 深圳市贝特瑞新能源材料股份有限公司 | Lithium ion battery SiO composite material as well as preparation method and application thereof |
| US20160211511A1 (en) * | 2015-01-20 | 2016-07-21 | Shenzhen Btr New Energy Materials Inc. | Nano-silicon composite negative electrode material used for lithium ion battery, process for preparing the same and lithium ion battery |
| CN106784732A (en) * | 2017-01-20 | 2017-05-31 | 吕铁铮 | A kind of carbon-coated nano silicon composite and its preparation method and application |
| CN107302080A (en) * | 2017-06-21 | 2017-10-27 | 天津爱敏特电池材料有限公司 | A kind of silica-base film negative material and preparation method thereof |
| CN107572529A (en) * | 2017-08-31 | 2018-01-12 | 北方奥钛纳米技术有限公司 | Non-crystalline silicon raw powder's production technology, non-crystalline silicon powder and lithium ion battery |
| US20180269519A1 (en) * | 2015-12-10 | 2018-09-20 | Lg Chem, Ltd. | Method of preparing negative electrode active material for lithium secondary battery and lithium secondary battery using the same |
| CN109638231A (en) * | 2017-10-09 | 2019-04-16 | 珠海市三顺纳米新材料有限公司 | Silicon monoxide composite cathode material and preparation method thereof and lithium ion battery |
| CN110299519A (en) * | 2019-06-18 | 2019-10-01 | 金雪莉 | A kind of crystalline silicon/oxygen silicon/carbon coating composite negative pole material and preparation method thereof |
| US20190305366A1 (en) * | 2016-11-07 | 2019-10-03 | Wacker Chemie Ag | Carbon-coated silicon particles for lithium ion batteries |
| CN110504430A (en) * | 2019-08-28 | 2019-11-26 | 陕西煤业化工技术研究院有限责任公司 | A kind of lithium ion battery silicon-carbon cathode material and preparation method thereof |
| CN110854368A (en) * | 2019-11-21 | 2020-02-28 | 陕西煤业化工技术研究院有限责任公司 | High-capacity silicon-carbon negative electrode precursor material and preparation method thereof |
-
2020
- 2020-07-06 CN CN202010639946.8A patent/CN111755682A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104282894A (en) * | 2013-07-08 | 2015-01-14 | 北京化工大学 | Preparation method of porous Si/C composite microsphere |
| CN104638237A (en) * | 2015-01-20 | 2015-05-20 | 深圳市贝特瑞新能源材料股份有限公司 | Lithium ion battery SiO composite material as well as preparation method and application thereof |
| US20160211511A1 (en) * | 2015-01-20 | 2016-07-21 | Shenzhen Btr New Energy Materials Inc. | Nano-silicon composite negative electrode material used for lithium ion battery, process for preparing the same and lithium ion battery |
| US20180269519A1 (en) * | 2015-12-10 | 2018-09-20 | Lg Chem, Ltd. | Method of preparing negative electrode active material for lithium secondary battery and lithium secondary battery using the same |
| US20190305366A1 (en) * | 2016-11-07 | 2019-10-03 | Wacker Chemie Ag | Carbon-coated silicon particles for lithium ion batteries |
| CN106784732A (en) * | 2017-01-20 | 2017-05-31 | 吕铁铮 | A kind of carbon-coated nano silicon composite and its preparation method and application |
| CN107302080A (en) * | 2017-06-21 | 2017-10-27 | 天津爱敏特电池材料有限公司 | A kind of silica-base film negative material and preparation method thereof |
| CN107572529A (en) * | 2017-08-31 | 2018-01-12 | 北方奥钛纳米技术有限公司 | Non-crystalline silicon raw powder's production technology, non-crystalline silicon powder and lithium ion battery |
| CN109638231A (en) * | 2017-10-09 | 2019-04-16 | 珠海市三顺纳米新材料有限公司 | Silicon monoxide composite cathode material and preparation method thereof and lithium ion battery |
| CN110299519A (en) * | 2019-06-18 | 2019-10-01 | 金雪莉 | A kind of crystalline silicon/oxygen silicon/carbon coating composite negative pole material and preparation method thereof |
| CN110504430A (en) * | 2019-08-28 | 2019-11-26 | 陕西煤业化工技术研究院有限责任公司 | A kind of lithium ion battery silicon-carbon cathode material and preparation method thereof |
| CN110854368A (en) * | 2019-11-21 | 2020-02-28 | 陕西煤业化工技术研究院有限责任公司 | High-capacity silicon-carbon negative electrode precursor material and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| 朱成良等: "硅烷法制备非晶硅粉的晶化研究", 《浙江理工大学学报》 * |
| 汪新颜等: "硅烷流量对硅烷热CVD法制备纳米硅粉的影响", 《浙江理工大学学报》 * |
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