CN113381024A - Silica negative electrode material, preparation method thereof and lithium ion battery - Google Patents

Silica negative electrode material, preparation method thereof and lithium ion battery Download PDF

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CN113381024A
CN113381024A CN202110734000.4A CN202110734000A CN113381024A CN 113381024 A CN113381024 A CN 113381024A CN 202110734000 A CN202110734000 A CN 202110734000A CN 113381024 A CN113381024 A CN 113381024A
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silicon
carbon
silicon oxide
oxygen
layer
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CN113381024B (en
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裴大钊
林文佳
曾汉民
徐悦斌
何巍
刘金成
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Eve Energy Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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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
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • 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
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Abstract

The invention provides a silica anode material, a preparation method thereof and a lithium ion battery. The silicon-oxygen anode material comprises a silicon-oxygen inner core, a carbon coating layer covering the silicon-oxygen inner core, and a carbon nano tube, wherein one end of the carbon nano tube is embedded into the carbon coating layer, and the other end of the carbon nano tube is free outside the carbon coating layer. The preparation method comprises the following steps: and placing one end of a carbon nano tube on the surface of the silicon oxide by using a template method to obtain a treated silicon oxide, coating a carbon layer on the surface of the treated silicon oxide, and carrying out heat treatment on the silicon oxide coated with the carbon layer to obtain the silicon-oxygen negative electrode material. The silica negative electrode material provided by the invention has excellent ionic conductivity and electronic conductivity and excellent cycle performance, and can optimize the dispersion of carbon nanotubes in a negative electrode plate.

Description

Silica negative electrode material, preparation method thereof and lithium ion battery
Technical Field
The invention belongs to the technical field of batteries, relates to a negative electrode material and a preparation method thereof, and a lithium ion battery, and particularly relates to a silica negative electrode material and a preparation method thereof, and a lithium ion battery.
Background
The four main materials of the lithium battery are: the lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte, wherein the ionic conductivity and the electronic conductivity of a positive electrode material and a negative electrode material have a decisive influence on the power density of the lithium battery. The ionic conductivity and the electronic conductivity of the negative electrode material are lower than those of the positive electrode material, so that the negative electrode material is a short plate for improving the power density of the lithium battery and determines the power density of the lithium battery.
Silica materials having a theoretical gram capacity of about 2500mAh/g have been successfully used in the negative electrode materials of lithium ion batteries, but the silicon materials are inferior to graphite materials in both semiconductor ionic conductivity and electronic conductivity. Therefore, the rate capability of the silica material is inferior to that of graphite, and lithium precipitation on the surface of the silica material can be caused in the rapid charging process. In order to improve the ionic conductivity and the electronic conductivity of the silicon-oxygen material, the surface of the silicon-oxygen material is coated with carbon, and a carbon layer with the thickness of 30-50nm is coated. The higher gram capacity results in the siloxane material inserting more lithium ions during the intercalation process, so the siloxane material expands up to about 180% during the intercalation process. The silicon-oxygen material can cause pulverization of the negative electrode material in the circulation process, silicon-oxygen of the carbon coating layer conducts lithium ions and electrons in a point contact mode, pulverization of the material causes damage of a negative electrode conductive network, and further polarization of the negative electrode is increased to cause deterioration of circulation performance. In order to improve the rate capability and the cycle performance of the silica material, carbon nanotubes are added in the homogenization process to improve the ionic conductivity and the electronic conductivity of the silica material and improve the damage of a negative electrode conductive network, but the carbon nanotubes have large specific surface area, so that the viscosity of slurry is greatly changed in the homogenization process, and the problem of uniform dispersion is solved.
CN110550635A discloses a preparation method of a novel carbon-coated silica negative electrode material, which comprises the steps of firstly, crushing massive SiO into powder, secondly, preparing a mixed precursor, taking pitch and SiO, mixing in proportion, carrying out ball milling homogenization, thirdly, carbonizing and coating, placing the mixed precursor obtained in the second step into a vacuum tube furnace, preparing a composite intermediate, fourthly, carrying out ball milling homogenization, taking out and ball milling the composite intermediate obtained in the third step to obtain a homogeneous composite intermediate, fifthly, carbonizing and coating, placing the composite intermediate obtained in the fourth step into the vacuum tube furnace again, introducing protective gas, and keeping the temperature for a certain time to obtain the carbon-coated silica composite negative electrode material.
CN111048756A discloses a high conductivity silicon-oxygen negative electrode material, which includes a silicon-based core and a coating layer formed on the surface of the silicon-based core, wherein the coating layer includes carbon and a fast ion conductor, and the fast ion conductor forms a complete ion transmission channel in the coating layer, directly connects with the silicon-based core, and extends to the surface of the coating layer.
CN110571412A discloses a silicon-based negative electrode material for a lithium ion battery, a preparation method and an application thereof, wherein the silicon-based negative electrode material comprises the following components in percentage by mass, based on 100% of the total mass of the silicon-based negative electrode material: 90-99.3% of silicon-based functional material, 0-5% of carbon black conductive agent, 0.1-5% of carbon nanotube conductive agent, 0.5-5% of binder, 0.1-2% of thickening agent and the balance of water; wherein, the carbon nano tube conductive agent is coated on the surface of the silicon-based functional material.
However, the ionic conductivity and the electronic conductivity of the product prepared by the scheme are still to be improved, and the cycle performance is further enhanced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a silica anode material, a preparation method thereof and a lithium ion battery. The silicon-oxygen cathode material provided by the invention is a radial silicon-oxygen material, has excellent ionic conductivity and electronic conductivity, and has excellent cycle performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a silicon-oxygen anode material, which includes a silicon-oxygen core, a carbon coating layer covering the silicon-oxygen core, and a carbon nanotube having one end embedded in the carbon coating layer and the other end free from the carbon coating layer.
In the silicon-oxygen cathode material provided by the invention, one end of the carbon nano tube is embedded into the carbon coating layer, the other end of the carbon nano tube is dissociated outside the carbon coating layer, the carbon nano tube forms a radial shape on the silicon-oxygen cathode material, and the silicon-oxygen cathode material with the special shape has excellent ionic conductivity and electronic conductivity and excellent cycle performance.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
As a preferable embodiment of the present invention, the carbon nanotube penetrates the carbon coating layer.
Preferably, one end of the carbon nano tube embedded carbon coating layer is perpendicular to the surface of the silica inner core.
Preferably, the carbon coating has a thickness of 30-50nm, such as 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, or the like. In the invention, if the thickness of the carbon coating layer is too thick, the gram capacity of the material is reduced; if the thickness of the carbon coating is too thin, there may be coating integrity problems.
Preferably, in the silicon-oxygen anode material, the mass fraction of the carbon coating layer is 5-15 wt%, such as 5 wt%, 7 wt%, 9 wt%, 10 wt%, 11 wt%, 13 wt% or 15 wt%.
As a preferred technical scheme of the invention, the silicon oxygen inner core comprises silicon and silicon dioxide.
Preferably, the silicon oxygen core further comprises a doping element. The doping element can be in the inner part of the silica inner core or on the surface layer of the silica inner core.
Preferably, the doping element is a metal element.
Preferably, the doping element includes a magnesium element and/or a lithium element. The advantage of the two doping elements is that the metal element with the lighter atomic mass is easily doped during the doping process.
Preferably, the mass fraction of doping elements in the silicon oxygen core is 5-15 wt%, such as 5 wt%, 7 wt%, 9 wt%, 10 wt%, 11 wt%, 13 wt% or 15 wt%, etc.
Preferably, the silica inner core also comprises silicate. The silicate is present only in the silicon oxygen core containing the doping element, which is generated as a result of the doping.
Preferably, the cation of the silicate is a doping element.
Preferably, the Si/O molar ratio in the silica core is in the range of 0.5 to 2, such as 0.5, 1, 1.5, or 2, and the like.
Preferably, the particle size D50 of the silica core is 4-6 μm, such as 4 μm, 4.5 μm, 5 μm, 5.5 μm, or 6 μm.
In a second aspect, the present invention provides a method for preparing the silicon-oxygen anode material according to the first aspect, wherein the method comprises the following steps:
and placing one end of a carbon nano tube on the surface of the silicon oxide by using a template method to obtain a treated silicon oxide, coating a carbon layer on the surface of the treated silicon oxide, and carrying out heat treatment on the silicon oxide coated with the carbon layer to obtain the silicon-oxygen negative electrode material.
In the preparation method provided by the invention, a complex carbon nanotube growth process is not required, the carbon nanotube can be compounded on the surface of silicon oxide on the basis of the existing carbon nanotube product, then carbon coating is carried out, finally heat treatment is carried out to realize disproportionation reaction of the silicon oxide (such as silicon monoxide) to obtain the silicon-oxygen composite cathode material, one end of the carbon nanotube in the cathode material is embedded into the carbon coating, the other end of the carbon nanotube is dissociated outside the carbon coating and presents a radial shape, and the carbon nanotube is uniformly dispersed, so that the performance of the silicon-oxygen composite cathode material is excellent.
In a preferred embodiment of the present invention, the silicon oxide is silicon monoxide. The disproportionation reaction of silicon monoxide to silicon and silicon dioxide can occur by heat treatment after the carbon layer is coated.
Preferably, the silicon oxide has the formula SiOx, wherein 0 < x < 2, e.g., x is 0.5, 1, or 1.5, etc.
Preferably, the preparation method of the silicon monoxide comprises the following steps: heating and gasifying silicon and silicon dioxide under the condition of vacuum pumping, and cooling to obtain the silicon monoxide.
Preferably, the degree of vacuum of the vacuum is 5-20Pa, such as 5Pa, 10Pa, 15Pa or 20 Pa.
Preferably, the temperature for heating and gasifying is 800-.
As a preferable technical scheme of the invention, the silicon oxide is subjected to crushing pretreatment before use.
Preferably, the crushing pretreatment includes coarse crushing and fine crushing. In the invention, the coarse crushing is to crush the massive silica powder into small particles with edges, and the fine crushing is to crush the small particles with edges after the coarse crushing to make the edges smooth and smooth.
Preferably, the disruption pretreatment disrupts the silicon oxide to a particle size D50 of 4-6 μm, such as 4 μm, 4.5 μm, 5 μm, 5.5 μm, or 6 μm, and the like.
Preferably, the one end of the carbon nanotube is placed on the surface of the silicon oxide using a templating method such that the carbon nanotube is perpendicular to the surface of the silicon oxide.
In the present invention, the template method may be a method using a template having a concave spherical shape, the concave spherical structure of the template having a concave cylindrical structure extending therefrom, silicon oxide being fixed in the concave spherical shape and carbon nanotubes being fixed in the concave cylindrical structure. The template is obtained by etching and/or photoetching the silicon wafer, and the method for dispersing the carbon nano tubes in the template can be that the template is placed in dispersion liquid of the carbon nano tubes, so that the carbon nano tubes are mixed with the template, and partial carbon nano tubes can enter the concave columnar structure of the template.
As a preferred embodiment of the present invention, the method for coating the carbon layer includes liquid phase coating and/or gas phase coating.
Preferably, the liquid phase coating includes mixing the treated silicon oxide with a non-gaseous carbon source, and then sintering to obtain the silicon oxide coated with the carbon layer.
The non-gaseous carbon source may be in a solid phase or a liquid phase.
Preferably, the non-gaseous carbon source comprises pitch.
Preferably, the sintering temperature is 800-.
Preferably, the sintering time is 2-4h, such as 2h, 2.5h, 3h, 3.5h or 4h, etc.
Preferably, the gas phase coating comprises introducing a gas phase carbon source to mix with the treated silicon oxide, and sintering to obtain the silicon oxide coated with the carbon layer.
Preferably, the gas phase carbon source comprises methane and/or ethane.
Preferably, the sintering temperature is 800-.
Preferably, the sintering time is 2-4h, such as 2h, 2.5h, 3h, 3.5h or 4h, etc.
As a preferred technical scheme of the invention, the temperature of the heat treatment is 800-.
Preferably, the time of the heat treatment is 2-4h, such as 2h, 2.5h, 3h, 3.5h or 4h, etc.
Preferably, the preparation method further comprises: and adding a doping element source to the silicon oxide coated with the carbon layer for doping before coating the carbon layer and/or before heat treatment after coating the carbon layer.
Preferably, the doping element source is a simple substance and/or a salt of a doping element.
Preferably, the simple substance of the doping element comprises a simple substance of magnesium and/or a simple substance of lithium.
Preferably, the doping element salt comprises a lithium salt and/or a magnesium salt.
As a further preferable technical scheme of the preparation method, the method comprises the following steps:
crushing the silicon monoxide to the particle size D50 of 4-6 μm, placing one end of a carbon nano tube on the surface of the silicon monoxide by using a template method to obtain the treated silicon monoxide, coating a carbon layer on the surface of the treated silicon monoxide by using a liquid phase coating and/or gas phase coating method, and carrying out heat treatment on the silicon monoxide coated with the carbon layer at 800-1200 ℃ for 2-4h to obtain the silicon oxygen cathode material;
wherein the preparation method of the silicon monoxide comprises the following steps: heating and gasifying silicon and silicon dioxide at 800-1500 ℃ under the condition of vacuumizing to the vacuum degree of 5-20Pa, and cooling to obtain the silicon protoxide;
the liquid phase coating comprises the steps of mixing the treated silicon monoxide with a non-gaseous carbon source, and sintering at 800-1200 ℃ for 2-4h to obtain the silicon monoxide coated with a carbon layer;
the gas phase coating comprises introducing a gas phase carbon source to be mixed with the treated silicon monoxide, and sintering at 800-1200 ℃ for 2-4h to obtain the silicon monoxide coated with the carbon layer;
adding a doping element source to the silicon oxide coated with the carbon layer for doping during the synthesis of the silicon oxide and/or adding the doping element source to the silicon oxide coated with the carbon layer for doping before the heat treatment after the coating of the carbon layer.
In a third aspect, the present invention provides a lithium ion battery comprising the silicon-oxygen negative electrode material according to the first aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) the silica negative electrode material provided by the invention has excellent ionic conductivity and electronic conductivity and excellent cycle performance, and can optimize the dispersion of carbon nanotubes in a negative electrode plate. The electronic conductivity of the silicon-oxygen cathode material provided by the invention can reach 0.64 multiplied by 102S/cm, and the capacity retention rate can reach 88% after 30 charge-discharge cycles.
(2) The preparation method provided by the invention is simple to operate, short in flow and easy for industrial large-scale production.
Drawings
FIG. 1 is a schematic flow chart of the preparation process of example 1.
Fig. 2 is a schematic structural diagram of the silicon-oxygen anode material provided in example 1, wherein 101-silicon dioxide, 102-silicon, 2-carbon coating layer, and 3-carbon nanotubes;
fig. 3 is a schematic view of a template used in the template method of example 1, and the inset in the figure is a partial enlarged view of the pore structure in the template.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The following are typical but non-limiting examples of the invention:
example 1
The embodiment provides a preparation method of a silicon-oxygen anode material, which comprises the following steps:
heating silicon and silicon dioxide at the molar ratio of 1:1 at 1200 ℃ for gasification under the condition of vacuumizing to the vacuum degree of 15Pa, rapidly cooling in the environment of 25 ℃ to obtain the SiO, coarsely crushing the SiO to obtain a crushed product with the particle size D50 of 5mm, and classifying and finely crushing the crushed product with the particle size D50 of 5 mu m by an airflow mill. One end of the carbon nanotube is placed on the surface of the SiO by a template method (the template is a template with a concave spherical shape prepared by photoetching a silicon wafer, as shown in figure 3, a concave column structure extends out of the concave spherical structure of the template, silicon oxide SiO is fixed in the concave spherical shape, and then the template is placed in 10g/mL of carbon nanotube water dispersion liquid, so that the carbon nanotube is mixed with the template, and the carbon nanotube can enter the concave cylindrical structure of the template to be fixed), and the SiO treated by the carbon nanotube is obtained. Mixing SiO treated by the carbon nano tube with asphalt (the mass of the asphalt is 10 wt% of the total mass of the asphalt and the SiO treated by the carbon nano tube), sintering for 3h at 1000 ℃ to obtain SiO coated with a carbon layer, carrying out heat treatment for 3h at 1000 ℃ on the SiO coated with the carbon layer, and carrying out grading demagnetization on the obtained product to obtain the silica negative electrode material.
The schematic flow chart of the preparation process of this example is shown in fig. 1.
A schematic structural diagram of the silicon-oxygen anode material prepared in this embodiment is shown in fig. 2, where the silicon-oxygen anode material includes a silicon-oxygen core, a carbon coating layer 2 covering the silicon-oxygen core, and a carbon nanotube 3 with one end embedded in the carbon coating layer 2 and the other end dissociated outside the carbon coating layer 2; the carbon nano tube 3 penetrates through the carbon coating layer 2, one end, embedded into the carbon coating layer 2, of the carbon nano tube 3 is perpendicular to the surface of the silica inner core, the thickness of the carbon coating layer 2 is 40nm, in the silica negative electrode material, the mass fraction of the carbon coating layer 2 is 10 wt%, the silica inner core comprises silicon 102 and silicon dioxide 101, the particle size D50 of the silica inner core is 5 micrometers, and the Si/O molar ratio in the silica inner core is 1.
The test results of the silicon-oxygen anode material prepared in this example are shown in table 1.
Example 2
The embodiment provides a preparation method of a silicon-oxygen anode material, which comprises the following steps:
silicon, silicon dioxide and magnesium (the molar ratio of silicon to silicon dioxide is 1:1, the mass of the magnesium is 10 wt% of the total mass of the silicon, silicon dioxide and magnesium) are heated and gasified at 1000 ℃ under the condition of vacuumizing to the vacuum degree of 10Pa, the silicon monoxide SiO is obtained after being rapidly cooled in the environment of 25 ℃, the SiO is coarsely crushed to obtain a crushed product with the D50 of 5mm, and the crushed product with the particle size D50 of 5 mu m is obtained after being classified and finely crushed by an airflow mill. Placing one end of a Carbon Nano Tube (CNTs) on the surface of SiO (the template is a template with a concave spherical shape prepared by photoetching a silicon wafer, the concave spherical structure of the template extends out of a concave column structure, silicon oxide SiO is fixed in the concave spherical shape, and then placing the template in 10g/mL of carbon nano tube aqueous dispersion to mix the carbon nano tube with the template, so that the carbon nano tube can enter the concave column structure of the template to be fixed), thereby obtaining the SiO treated by the carbon nano tube. And introducing ethane gas into the SiO treated by the carbon nano tube at the flow rate of 20L/min, sintering for 3h at 1000 ℃ to obtain SiO coated with a carbon layer, carrying out heat treatment for 3h at 1000 ℃ on the SiO coated with the carbon layer, and carrying out graded demagnetization on the obtained product to obtain the silicon-oxygen negative electrode material.
The silicon-oxygen anode material prepared by the embodiment comprises a silicon-oxygen core, a carbon coating layer covering the silicon-oxygen core, and a carbon nanotube, wherein one end of the carbon nanotube is embedded in the carbon coating layer, and the other end of the carbon nanotube is dissociated outside the carbon coating layer; the carbon nano tube penetrates through the carbon coating layer, one end, embedded into the carbon coating layer, of the carbon nano tube is perpendicular to the surface of the silica inner core, the thickness of the carbon coating layer is 35nm, the mass fraction of the carbon coating layer in the silica negative electrode material is 7 wt%, the silica inner core comprises silicon, silicon dioxide and magnesium silicate, and the particle size D50 of the silica inner core is 5 microns; in the silica core, the Si/O molar ratio is 1, and the mass fraction of the magnesium element is 10 wt%.
The test results of the silicon-oxygen anode material prepared in this example are shown in table 1.
Example 3
The embodiment provides a preparation method of a silicon-oxygen anode material, which comprises the following steps:
heating and gasifying silicon, silicon dioxide and lithium elementary substances (the molar ratio of the silicon to the silicon dioxide is 1:3, and the mass of the lithium elementary substance is 5 wt% of the total mass of the silicon, the silicon dioxide and the lithium elementary substances) at 1500 ℃ under the condition of vacuumizing to 5Pa, rapidly cooling in an environment at 15 ℃ to obtain SiOx, wherein x is 1.5, coarsely crushing the SiOx to obtain a crushed product with the D50 of 5mm, and classifying and finely crushing the crushed product through an airflow mill to obtain a crushed product with the particle size D50 of 4 mu m. One end of the carbon nano tube is arranged on the surface of SiOx by a template method (the template is a template which is made by photoetching a silicon wafer and is provided with a concave spherical shape, a concave column structure extends out of the concave spherical structure of the template, silicon oxide SiOx is fixed in the concave spherical shape, and then the template is arranged in 8g/mL carbon nano tube aqueous dispersion to mix the carbon nano tube with the template, so that the carbon nano tube can enter the concave column structure of the template to be fixed), and the SiOx processed by the carbon nano tube is obtained. And introducing methane gas into the SiOx treated by the carbon nano tube at the flow rate of 10L/min, sintering for 4h at 800 ℃ to obtain the SiOx coated with the carbon layer, carrying out heat treatment for 4h at 800 ℃ on the SiOx coated with the carbon layer, and carrying out grading demagnetization on the obtained product to obtain the silicon-oxygen negative electrode material.
The silicon-oxygen anode material prepared by the embodiment comprises a silicon-oxygen core, a carbon coating layer covering the silicon-oxygen core, and a carbon nanotube, wherein one end of the carbon nanotube is embedded in the carbon coating layer, and the other end of the carbon nanotube is dissociated outside the carbon coating layer; the carbon nano tube penetrates through the carbon coating layer, one end, embedded into the carbon coating layer, of the carbon nano tube is perpendicular to the surface of the silica inner core, the thickness of the carbon coating layer is 30nm, the mass fraction of the carbon coating layer in the silica negative electrode material is 5 wt%, the silica inner core comprises silicon, silicon dioxide and lithium silicate, and the particle size D50 of the silica inner core is 4 microns; in the silica core, the Si/O molar ratio is 2/3, and the mass fraction of lithium element is 5 wt%.
The test results of the silicon-oxygen anode material prepared in this example are shown in table 1.
Example 4
The embodiment provides a preparation method of a silicon-oxygen anode material, which comprises the following steps:
heating and gasifying silicon and silicon dioxide (the molar ratio of the silicon to the silicon dioxide is 3:1) at 800 ℃ under the condition of vacuumizing to 20Pa, rapidly cooling in an environment at 30 ℃ to obtain the SiOx, wherein x is 0.5, coarsely crushing the SiOx to obtain a crushed product with the D50 of 5mm, and classifying and finely crushing the crushed product through an air flow mill to obtain a crushed product with the particle size D50 of 6 mu m. One end of the carbon nano tube is placed on the surface of SiOx by a template method (the template is a template which is made by photoetching a silicon wafer and is provided with a concave spherical shape, a concave column structure extends out of the concave spherical structure of the template, silicon oxide SiOx is fixed in the concave spherical shape, and then the template is placed in 15g/mL of carbon nano tube aqueous dispersion, so that the carbon nano tube is mixed with the template, and the carbon nano tube can enter the concave cylindrical structure of the template to be fixed), and the SiOx processed by the carbon nano tube is obtained. Mixing SiOx treated by carbon nano tubes with asphalt and magnesium salt (the mass of the asphalt is 15 wt% of the total mass of the SiOx treated by the asphalt, the magnesium salt and the carbon nano tubes, and the mass of magnesium element in the magnesium salt is 15 wt% of the total mass of the SiOx and the magnesium salt), sintering at 1200 ℃ for 2h to obtain the SiOx coated with a carbon layer, carrying out heat treatment at 1200 ℃ for 2h on the SiOx coated with the carbon layer, and carrying out grading demagnetization on the obtained product to obtain the silicon-oxygen negative electrode material.
The silicon-oxygen anode material prepared by the embodiment comprises a silicon-oxygen core, a carbon coating layer covering the silicon-oxygen core, and a carbon nanotube, wherein one end of the carbon nanotube is embedded in the carbon coating layer, and the other end of the carbon nanotube is dissociated outside the carbon coating layer; the carbon nano tube penetrates through the carbon coating layer, one end, embedded into the carbon coating layer, of the carbon nano tube is perpendicular to the surface of the silica inner core, the thickness of the carbon coating layer is 50nm, the mass fraction of the carbon coating layer in the silica negative electrode material is 15 wt%, the silica inner core comprises silicon, silicon dioxide and magnesium silicate, and the particle size D50 of the silica inner core is 6 microns; in the silica core, the Si/O molar ratio is 2, and the mass fraction of the magnesium element is 15 wt%.
The test results of the silicon-oxygen anode material prepared in this example are shown in table 1.
Comparative example 1
This comparative example was conducted in the same manner as example 1, except that the fixing of the carbon nanotubes on the SiO was not conducted by the template method, but instead, the carbon nanotubes were deposited on the surface of the SiO by mixing the aqueous dispersion of carbon nanotubes of 10g/mL with the SiO and evaporating the water.
The test results of the silicon oxide negative electrode material prepared in this comparative example are shown in table 1.
Test method
The silicon-oxygen cathode materials prepared in the examples and the comparative examples are prepared into cathodes, and in the cathode coating, the mass ratio of the silicon-oxygen cathode material to the conductive agent acetylene black and the binder SBR is 94:3: 3. Taking a lithium sheet as a positive electrode, using a PP diaphragm and 1mol/L LiPF as electrolyte6+ EC + EMC, to prepare test cells for performance testing.
A blue battery test system is adopted to carry out charging (charging step: 0.1C constant current to 0.005V and constant voltage to 0.005C) and discharging (discharging step: 0.1C constant current to 1.5V) tests at 25 ℃.
The test results are shown in the following table:
TABLE 1
Figure BDA0003140836990000121
It can be known from the above examples and comparative examples that the silica negative electrode materials provided in examples 1 to 3 have excellent ionic conductivity and electronic conductivity, and excellent cycle performance, and the silica negative electrode material provided by the present invention can optimize the dispersion of the carbon nanotubes in the negative electrode sheet.
Example 4 has excellent ionic conductivity and electronic conductivity because the carbon coating layer is thick. Since the Si/O molar ratio is high and the doping quality of magnesium element is high, the first effect is high, the gram capacity is high due to the high Si content, but the cycle decay is deteriorated.
The silicon-oxygen cathode material provided by the comparative example 1 has the advantages that the carbon nanotubes are not fixed by using a template method, so that the carbon nanotubes are dispersed and unevenly agglomerated, and the electronic conductivity and the first effect of the silicon-oxygen cathode material are obviously reduced compared with those of the example 1.
The applicant states that the present invention is illustrated by the above examples to the silicon-based composite anode material and the preparation method thereof, but the present invention is not limited to the above process steps, i.e. it does not mean that the present invention must rely on the above process steps to be implemented. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims (10)

1. The silicon-oxygen anode material is characterized by comprising a silicon-oxygen inner core, a carbon coating layer covering the silicon-oxygen inner core, and carbon nanotubes, wherein one end of each carbon nanotube is embedded in the carbon coating layer, and the other end of each carbon nanotube is free outside the carbon coating layer.
2. The silicon oxygen anode material of claim 1, wherein the carbon nanotubes penetrate a carbon coating layer;
preferably, one end of the carbon nano tube embedded carbon coating layer is vertical to the surface of the silica inner core;
preferably, the thickness of the carbon coating layer is 30-50 nm;
preferably, in the silicon-oxygen anode material, the mass fraction of the carbon coating layer is 5-15 wt%.
3. The silicon oxygen anode material of claim 1 or 2, wherein the silicon oxygen core comprises silicon and silicon dioxide;
preferably, the silicon oxygen inner core also comprises a doping element;
preferably, the doping element is a metal element;
preferably, the doping element comprises a magnesium element and/or a lithium element;
preferably, in the silicon oxygen inner core, the mass fraction of the doping element is 5-15 wt%;
preferably, the silica inner core also comprises silicate;
preferably, the cation of the silicate is a doping element;
preferably, in the silica core, the Si/O molar ratio is 0.5-2;
preferably, the particle size D50 of the silica inner core is 4-6 μm.
4. A method of preparing a silicon oxygen anode material according to any of claims 1 to 3, characterized in that the method comprises the following steps:
and placing one end of a carbon nano tube on the surface of the silicon oxide by using a template method to obtain a treated silicon oxide, coating a carbon layer on the surface of the treated silicon oxide, and carrying out heat treatment on the silicon oxide coated with the carbon layer to obtain the silicon-oxygen negative electrode material.
5. The production method according to claim 4, wherein the silicon oxide is a silicon oxide;
preferably, the chemical formula of the silicon monoxide is SiOx, wherein 0 < x < 2;
preferably, the preparation method of the silicon monoxide comprises the following steps: heating and gasifying silicon and silicon dioxide under the condition of vacuum pumping, and cooling to obtain the silicon monoxide;
preferably, the vacuum degree of the vacuumizing is 5-20 Pa;
preferably, the temperature of the heating gasification is 800-1500 ℃.
6. The method according to claim 4 or 5, wherein the silicon oxide is subjected to a crushing pretreatment before use;
preferably, the crushing pretreatment includes coarse crushing and fine crushing;
preferably, the crushing pretreatment crushes the silicon oxide to a particle size D50 of 4 to 6 μm;
preferably, the one end of the carbon nanotube is placed on the surface of the silicon oxide using a templating method such that the carbon nanotube is perpendicular to the surface of the silicon oxide.
7. The production method according to any one of claims 4 to 6, wherein the method of coating the carbon layer comprises liquid phase coating and/or gas phase coating;
preferably, the liquid phase coating comprises mixing the treated silicon oxide with a non-gaseous carbon source, and sintering to obtain a silicon oxide coated with a carbon layer;
preferably, the non-gaseous carbon source comprises pitch and/or resin;
preferably, the sintering temperature is 800-1200 ℃;
preferably, the sintering time is 2-4 h;
preferably, the gas-phase coating comprises introducing a gas-phase carbon source to mix with the treated silicon oxide, and sintering to obtain the silicon oxide coated with the carbon layer;
preferably, the gas phase carbon source comprises methane and/or ethane;
preferably, the sintering temperature is 800-1200 ℃;
preferably, the sintering time is 2-4 h.
8. The method according to any one of claims 4-7, wherein the temperature of the heat treatment is 800-1200 ℃;
preferably, the time of the heat treatment is 2-4 h;
preferably, the preparation method further comprises: adding a doping element source to dope when synthesizing the silicon oxide and/or adding the doping element source to the silicon oxide coated with the carbon layer for doping before heat treatment after coating the carbon layer;
preferably, the doping element source is a simple substance and/or a salt of a doping element.
9. The method for preparing according to any one of claims 4 to 8, characterized in that it comprises the steps of:
crushing the silicon monoxide to the particle size D50 of 4-6 μm, placing one end of a carbon nano tube on the surface of the silicon monoxide by using a template method to obtain the treated silicon monoxide, coating a carbon layer on the surface of the treated silicon monoxide by using a liquid phase coating and/or gas phase coating method, and carrying out heat treatment on the silicon monoxide coated with the carbon layer at 800-1200 ℃ for 2-4h to obtain the silicon oxygen cathode material;
wherein the preparation method of the silicon monoxide comprises the following steps: heating and gasifying silicon and silicon dioxide at 800-1500 ℃ under the condition of vacuumizing to the vacuum degree of 5-20Pa, and cooling to obtain the silicon protoxide;
the liquid phase coating comprises the steps of mixing the treated silicon monoxide with a non-gaseous carbon source, and sintering at 800-1200 ℃ for 2-4h to obtain the silicon monoxide coated with a carbon layer;
the gas phase coating comprises introducing a gas phase carbon source to be mixed with the treated silicon monoxide, and sintering at 800-1200 ℃ for 2-4h to obtain the silicon monoxide coated with the carbon layer;
adding a doping element source to the silicon oxide coated with the carbon layer for doping during the synthesis of the silicon oxide and/or adding the doping element source to the silicon oxide coated with the carbon layer for doping before the heat treatment after the coating of the carbon layer.
10. A lithium ion battery comprising the silicone negative electrode material according to any one of claims 1 to 3.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117673335A (en) * 2024-01-31 2024-03-08 贝特瑞新材料集团股份有限公司 Negative electrode material, preparation method thereof and lithium ion battery
CN117747803A (en) * 2023-12-20 2024-03-22 宣城矽立科新材料有限公司 Silicon-oxygen negative electrode material for improving conductivity and preparation method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104609366A (en) * 2015-02-13 2015-05-13 武汉理工大学 Manufacturing method of high aspect ratio micro structure of novel carbon-carbon nano tube composite material
CN110112378A (en) * 2019-04-02 2019-08-09 深圳市三顺纳米新材料股份有限公司 Lithium ion battery silicon oxygen composite negative pole material and preparation method thereof
CN111342030A (en) * 2020-03-28 2020-06-26 兰溪致德新能源材料有限公司 Multi-element composite high-first-efficiency lithium battery negative electrode material and preparation method thereof
CN111816859A (en) * 2020-07-22 2020-10-23 贝特瑞新材料集团股份有限公司 Silicon-based negative electrode material, preparation method thereof and lithium ion secondary battery
CN112234174A (en) * 2020-10-14 2021-01-15 江西壹金新能源科技有限公司 Lithium ion battery cathode material and preparation method thereof
CN112928237A (en) * 2021-01-22 2021-06-08 惠州亿纬锂能股份有限公司 Silicon-oxygen composite material, preparation method thereof and application thereof in battery

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104609366A (en) * 2015-02-13 2015-05-13 武汉理工大学 Manufacturing method of high aspect ratio micro structure of novel carbon-carbon nano tube composite material
CN110112378A (en) * 2019-04-02 2019-08-09 深圳市三顺纳米新材料股份有限公司 Lithium ion battery silicon oxygen composite negative pole material and preparation method thereof
CN111342030A (en) * 2020-03-28 2020-06-26 兰溪致德新能源材料有限公司 Multi-element composite high-first-efficiency lithium battery negative electrode material and preparation method thereof
CN111816859A (en) * 2020-07-22 2020-10-23 贝特瑞新材料集团股份有限公司 Silicon-based negative electrode material, preparation method thereof and lithium ion secondary battery
CN112234174A (en) * 2020-10-14 2021-01-15 江西壹金新能源科技有限公司 Lithium ion battery cathode material and preparation method thereof
CN112928237A (en) * 2021-01-22 2021-06-08 惠州亿纬锂能股份有限公司 Silicon-oxygen composite material, preparation method thereof and application thereof in battery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117747803A (en) * 2023-12-20 2024-03-22 宣城矽立科新材料有限公司 Silicon-oxygen negative electrode material for improving conductivity and preparation method thereof
CN117673335A (en) * 2024-01-31 2024-03-08 贝特瑞新材料集团股份有限公司 Negative electrode material, preparation method thereof and lithium ion battery

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