CN111435732B - Negative electrode material of lithium ion battery, preparation method of negative electrode material and lithium ion battery - Google Patents

Negative electrode material of lithium ion battery, preparation method of negative electrode material and lithium ion battery Download PDF

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CN111435732B
CN111435732B CN201911335660.4A CN201911335660A CN111435732B CN 111435732 B CN111435732 B CN 111435732B CN 201911335660 A CN201911335660 A CN 201911335660A CN 111435732 B CN111435732 B CN 111435732B
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composite particles
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CN111435732A (en
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赵晓锋
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Svolt Energy Technology Co Ltd
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    • 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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Abstract

The invention provides a negative electrode material of a lithium ion battery, a preparation method of the negative electrode material and the lithium ion battery. The negative electrode material comprises: graphene-silicon composite particles; the carbon layer is coated on the surface of the graphene-silicon composite particles; and the lithium salt layer is coated on the surface of the carbon layer, which is far away from the graphene-silicon composite particles. Therefore, the graphene-silicon composite particles have better conductivity and lower expansion rate, and the stability of the anode material can be effectively ensured; the coating of the carbon layer can reduce the specific surface area of the anode material, improve the first efficiency (first charge-discharge efficiency) of the lithium ion battery, and the coating of the carbon layer can not influence the gram capacity of the anode material; the lithium salt layer is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, so that the cycle performance of the lithium ion battery can be improved, and meanwhile, the lithium salt layer and the electrolyte have good compatibility so as to improve the stability of the lithium ion battery.

Description

Negative electrode material of lithium ion battery, preparation method of negative electrode material and lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a negative electrode material of a lithium ion battery, a preparation method of the negative electrode material and the lithium ion battery.
Background
With the increase of the energy density requirements of electric automobiles on lithium ion batteries, the negative electrode materials used for the lithium ion batteries are required to have high specific capacity and cycle life. However, currently commercialized lithium ion batteries generally adopt graphite carbon materials as negative electrode materials, and due to the lower theoretical electrochemical capacity (theoretical capacity 372 mAh/g), the requirements of high specific capacity lithium ion batteries are difficult to meet. The silicon-carbon negative electrode material is a novel energy storage negative electrode material developed in recent years, but has high expansion rate and poor conductivity, and the serious volume effect generated during electrochemical lithium intercalation and deintercalation causes the destruction of material structure and mechanical pulverization, so that the electrode materials are separated from each other and the electrode material and the current collector are separated, and further electric contact is lost, so that the cycle performance of the electrode is drastically reduced.
Accordingly, research on negative electrode materials of lithium ion batteries is in progress.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a negative electrode material for a lithium ion battery, which has better conductivity or better stability.
In one aspect of the invention, a negative electrode material for a lithium ion battery is provided. According to an embodiment of the present invention, the anode material includes: graphene-silicon composite particles; the carbon layer is coated on the surface of the graphene-silicon composite particles; and the lithium salt layer is coated on the surface of the carbon layer, which is far away from the graphene-silicon composite particles. Therefore, the graphene-silicon composite particles have better conductivity and lower expansion rate, and the stability of the anode material can be effectively ensured; the surface area of the anode material can be reduced by coating the carbon layer, the first efficiency (first charge and discharge efficiency) of the lithium ion battery is improved, and the gram capacity of the anode material is not influenced by coating the carbon layer; the lithium salt layer is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, so that the cycle performance of the lithium ion battery can be improved, and meanwhile, the lithium salt layer and the electrolyte have good compatibility so as to improve the stability of the lithium ion battery.
According to an embodiment of the present invention, the ratio of the particle diameter of the graphene-silicon composite particles, the thickness of the carbon layer, and the thickness of the lithium salt layer is 100: (1-10): (1-10), optionally, the lithium salt layer has a thickness of 5-100 nanometers.
According to an embodiment of the present invention, the material of the lithium salt layer is Li 1+(x+y) A x B y Ti 2-(x+y) (PO4) 3 Wherein A is a tetravalent element, B is a divalent element, 0<x is less than or equal to 1 and 0<y is less than or equal to 1, wherein A is selected from at least one of Zr, nb, mo, ce, cr, ge, ru, se, sn, ta, tb, V, W, and B is selected from at least one of Mg, zn, cu, ca, sr, ba, cd, fe, mn, nd, yb.
According to the embodiment of the invention, the particle size of the anode material is 5-20 micrometers, and optionally, the graphene silicon composite particles are nitrogen-doped graphene silicon composite particles.
In another aspect of the invention, a method of preparing a negative electrode material for a lithium ion battery is provided. According to an embodiment of the present invention, a method of preparing a negative electrode material of a lithium ion battery includes: dispersing and mixing graphene-silicon composite particles with an organic carbon source solution, and carbonizing to obtain a first composite material with a carbon layer coating the graphene-silicon composite particles; and forming a lithium salt layer on the surface of the first composite material through physical vapor deposition so as to obtain the anode material. Therefore, the graphene-silicon composite particles have better conductivity and lower expansion rate, and the stability of the anode material can be effectively ensured; the coating of the carbon layer can reduce the specific surface area of the anode material, improve the first efficiency (first charge-discharge efficiency) of the lithium ion battery, and the coating of the carbon layer can not influence the gram capacity of the anode material; the lithium salt layer is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, so that the cycle performance of the lithium ion battery can be improved, and meanwhile, the lithium salt layer and the electrolyte have good compatibility; moreover, the lithium salt layer is prepared by physical vapor deposition, so that the lithium salt layer which is controllable in thickness, high in density and uniformly coated on the surface of the carbon layer can be obtained, and the risk that the carbon layer or graphene silicon composite particles are contacted with electrolyte due to uneven coating of the lithium salt layer is avoided.
According to an embodiment of the present invention, the physical vapor deposition conditions are: the temperature is 100-300 ℃ and the vacuum degree is 1 x 10 -4 ～10*10 -4 Pa, the time is 10-120 minutes, and the distance between the target material lithium salt and the first composite material is 1-1000 mm.
According to the embodiment of the invention, the mass ratio of the graphene silicon composite particles to the organic carbon source is 1-5: 10 to 30 percent.
According to the embodiment of the invention, the graphene silicon composite particles are nitrogen-doped graphene silicon composite particles.
According to the embodiment of the invention, graphene oxide dispersion liquid, copper ammonia solution, nitrogen source and aqueous nano silicon solution are mixed, and the mixed solution after mixing is reacted for 2 to 12 hours at the temperature of 150 to 200 ℃ in a high-pressure reaction kettle so as to obtain the nitrogen-doped graphene silicon composite particles,
optionally, the dosage of the graphene oxide dispersion liquid is 1000mL, and the concentration is 1-10 mg/mL; the consumption of the copper ammonia solution is 100mL, and the concentration is 0.1-0.5 mol/L; the dosage of the nitrogen source is 1-5 mL; the dosage of the aqueous nano silicon solution is 100mL, and the mass concentration is 1% -10%.
In yet another aspect of the invention, a lithium ion battery is provided. According to an embodiment of the invention, the lithium ion battery comprises the anode material. Therefore, the lithium ion battery has better battery performances such as cycle performance, gram capacity, charge and discharge performance, capacitance retention rate and the like. Those skilled in the art will appreciate that the lithium ion battery has all of the features and advantages of the foregoing negative electrode material, and will not be described in detail herein.
Drawings
Fig. 1 is a schematic structural view of a negative electrode material of a lithium ion battery according to an embodiment of the present invention.
Fig. 2 is a flow chart of a method of preparing a negative electrode material for a lithium ion battery in accordance with another embodiment of the invention.
Fig. 3 is a schematic structural view of a first composite material according to yet another embodiment of the present invention.
Fig. 4 is a scanning electron microscope image of the anode material prepared in example 1.
Detailed Description
Embodiments of the present invention are described in detail below. The following examples are illustrative only and are not to be construed as limiting the invention. The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
In one aspect of the invention, a negative electrode material for a lithium ion battery is provided. According to an embodiment of the present invention, referring to fig. 1, the anode material 100 includes: graphene-silicon composite particles 10; the carbon layer 20 is coated on the surface of the graphene-silicon composite particles 10; and the lithium salt layer 30 is coated on the surface of the carbon layer 20 far away from the graphene-silicon composite particles 10. Therefore, the graphene-silicon composite particles 10 have better conductivity and lower expansion rate, so that the stability of the anode material can be effectively ensured; the coating of the carbon layer 20 can reduce the specific surface area of the anode material, improve the first efficiency (first charge-discharge efficiency) of the lithium ion battery, and the coating of the carbon layer 20 can not influence the gram capacity of the anode material; the lithium salt layer 30 is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, so that the cycle performance of the lithium ion battery can be improved, and meanwhile, the lithium salt layer 30 and the electrolyte have good compatibility so as to improve the stability of the lithium ion battery.
According to the embodiment of the invention, the graphene silicon composite particles are nitrogen-doped graphene silicon composite particles. Thus, by doping nitrogen, the specific capacity of graphene and the conductivity of the negative electrode material can be effectively improved, and the specific capacity (i.e., gram capacity) of the negative electrode material can be further improved.
According to the embodiment of the invention, the carbon layer is amorphous carbon, so that the battery performance of the lithium ion battery can be better improved.
According to an embodiment of the present invention, the material of the lithium salt layer is Li 1+(x+y) A x B y Ti 2-(x+y) (PO4) 3 Wherein A is a tetravalent element, B is a divalent element, 0<x is less than or equal to 1 and 0<y is less than or equal to 1, wherein A is selected from at least one of Zr, nb, mo, ce, cr, ge, ru, se, sn, ta, tb, V, W, and B is selected from at least one of Mg, zn, cu, ca, sr, ba, cd, fe, mn, nd, yb. Therefore, the lithium salt layer is composite lithium salt, so that lithium ions of the lithium ion battery can be transmitted under the condition of high multiplying power, the compatibility of the lithium salt layer 30 made of the material and electrolyte is better, the cycle performance of the lithium ion battery can be improved, and furthermore, various metal elements in the composite lithium salt have a certain synergistic effect, and the conductivity of lithium ions in the lithium salt layer and the structural stability of the lithium salt layer can be improved better.
According to an embodiment of the present invention, referring to fig. 1, the ratio of the particle diameter D1 of the graphene-silicon composite particles, the thickness D2 of the carbon layer, and the thickness D3 of the lithium salt layer is 100: (1-10): (1-10), such as 100:1:1, 100:1:2, 100:1:4, 100:1:6, 100:1:8, 100:1:10, 100:2:10, 100:5:10, 100:10:10, 100:2:4, 100:4:6, 100:2:8, etc. The negative electrode material in the proportion range can ensure that the thicknesses of the carbon layer and the lithium salt layer are relatively thinner, thereby being beneficial to improving the gram capacity of the negative electrode material.
According to an embodiment of the present invention, the thickness of the lithium salt layer is 5 to 100 nanometers, such as 5 nanometers, 10 nanometers, 15 nanometers, 20 nanometers, 25 nanometers, 30 nanometers, 40 nanometers, 50 nanometers, 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, or 100 nanometers. Therefore, the lithium salt layer with the thickness can completely and uniformly cover the carbon layer, and the thinner lithium salt layer cannot influence the gram capacity and other battery performances of the anode material; if the thickness is less than 30 nm, the carbon layer may not be completely and uniformly coated; if the thickness is greater than 100nm, the gram capacity of the lithium ion battery is relatively low.
According to an embodiment of the present invention, the particle size of the negative electrode material is 5 to 20 microns, such as 5 microns, 6 microns, 8 microns, 10 microns, 12 microns, 14 microns, 16 microns, 18 microns, 20 microns. Thus, the anode material has proper specific surface area, so that the anode material has better activity; if the particle size is smaller than 5 microns, the processing difficulty is high, the specific surface area of the anode material is larger, and the first efficiency of the anode material is lower; if the particle size is larger than 20 microns, the dynamic performance of the material is deviated, the compaction density is lower, the specific surface area of the anode material is smaller, and the activity improvement and the rate capability of the anode material are not facilitated.
In another aspect of the invention, a method of preparing a negative electrode material for a lithium ion battery is provided. According to an embodiment of the present invention, referring to fig. 2, a method of preparing a negative electrode material of a lithium ion battery includes:
s100: the graphene-silicon composite particles 10 and the organic carbon source solution are dispersed and mixed, and the first composite material of the graphene-silicon composite particles 10 coated by the carbon layer 20 is obtained through carbonization treatment, and the structural schematic diagram is shown in fig. 3. Therefore, the graphene-silicon composite particles 10 have better conductivity and lower expansion rate, so that the stability of the anode material can be effectively ensured; the coating of the carbon layer 20 can reduce the surface area of the anode material, improve the first efficiency (first charge-discharge efficiency) of the lithium ion battery, and the coating of the carbon layer 20 does not affect the gram capacity of the anode material.
Wherein, after carbonization treatment, the method further comprises the step of crushing the first composite material so as to obtain the first composite material with proper particle size, so that the subsequent lithium salt is uniformly and completely coated on the surface of the first composite material (namely, the surface of the carbon layer).
According to an embodiment of the present invention, the organic carbon source in the organic carbon source solution is at least one of sucrose, glucose, phenolic resin, epoxy resin, polyacrylonitrile, polyvinyl chloride, polyurethane, polypropylene, melamine, asphalt, tar, cellulose, lignin, starch, and fruit shell. Therefore, the material and the graphene silicon composite particles can not generate side reaction, a layer of relatively uniform carbon layer can be formed on the surface of the graphene silicon composite particles through carbonization treatment, and the material is wide in source and low in cost. The solvent in the organic carbon source solution is not particularly required as long as the organic carbon source can be well dissolved.
According to the embodiment of the invention, the graphene silicon composite particles are nitrogen-doped graphene silicon composite particles. Thus, by doping nitrogen, the specific capacity of graphene and the conductivity of the negative electrode material can be effectively improved, and the specific capacity (i.e., gram capacity) of the negative electrode material can be further improved.
According to the embodiment of the invention, the mass ratio of the graphene silicon composite particles (or the nitrogen-doped graphene silicon composite particles) to the organic carbon source is 1-5: 10-30, such as 1:10, 1:15, 1:20, 1:25, 1:30, 3:10, 3:15, 3:20, 3:25, 3:30, 5:10, 5:15, 5:20, 5:25, 5:30. Therefore, a carbon layer can be formed on the surface of the graphene-silicon composite particles completely and uniformly, the thickness of the carbon layer is proper, the thickness of the carbon layer cannot be thicker (otherwise, the gram capacity of the cathode material can be influenced), and if the mass ratio of the organic carbon source is lower, the carbon layer can not completely cover the surface of the graphene-silicon composite particles.
According to an embodiment of the present invention, graphene oxide dispersion liquid, copper ammonia solution, nitrogen source and aqueous nano silicon solution are mixed, and the mixed solution after mixing is reacted in a high pressure reaction kettle (pressure is 1 to 5 Mpa) at 150 to 200 ℃ (such as 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ or 200 ℃) for 2 to 12 hours, so as to obtain nitrogen-doped graphene silicon composite particles. Under the conditions of high pressure and high temperature, the liquid raw material is gasified, so that even doping of the solid raw material (graphene oxide) and the liquid raw material can be realized, meanwhile, the graphene oxide is oxidized by the oxidant copper ammonia solution, hydroxyl/carboxyl on the surface of the graphene is combined, then the temperature and the pressure are reduced, dehydration is carried out, and the hydrogel material is left (the nitrogen-doped graphene silicon composite particles are obtained after the subsequent drying and dehydration). Therefore, graphene oxide and nano silicon can be uniformly dispersed and mixed in a high-pressure reaction kettle by a hydrothermal method, so that the high-density nitrogen-doped graphene silicon composite particles are prepared, the expansion rate of the nitrogen-doped graphene silicon composite particles is reduced, and the conductivity of the nitrogen-doped graphene silicon composite particles is improved; the copper ammonia solution is adopted, so that the surface of graphene oxide can be oxidized to form carboxyl/hydroxyl groups, the material is dehydrated to form hydrogel conveniently, meanwhile, the copper ammonia solution oxidant has weak oxidizing property, does not damage the self structure of the material, contains copper substances, and can be used as a negative electrode material to improve the capacity and the conductivity; further, the evaporation of water in the subsequent vacuum drying process can enable the nitrogen-doped graphene-silicon composite particles to have nano/micron pores, namely, the purpose of pore forming in the nitrogen-doped graphene-silicon composite particles is achieved, so that an expansion space is provided for silicon in the nitrogen-doped graphene-silicon composite particles, and the expansion rate of the whole size of the nitrogen-doped graphene-silicon composite particles is reduced; in addition, when the nitrogen-doped graphene-silicon composite particles are prepared by a hydrothermal method, the raw materials are gasified and then cooled to form the nitrogen-doped graphene-silicon composite particles with higher density, so that the negative electrode material has higher tap density and smaller aperture, and further lithium storage of the negative electrode material is facilitated, and the specific capacity of the negative electrode material is improved.
In the preparation of the nitrogen-doped graphene silicon composite particles, the dosage of the graphene oxide dispersion liquid is 1000mL, and the concentration is 1-10 mg/mL (such as 1mg/mL, 2mg/mL, 4mg/mL, 6mg/mL, 8mg/mL and 10 mg/mL); the consumption of the copper ammonia solution is 100mL, and the concentration is 0.1-0.5 mol/L (such as 0.1mol/L, 0.2mol/L, 0.3mol/L, 0.4mol/L and 0.5 mol/L); the nitrogen source is used in an amount of 1-5 mL, such as 1mL, 2mL, 3mL, 4mL and 5mL; the dosage of the aqueous nano silicon solution is 100mL, and the mass concentration is 1% -10% (such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%). Therefore, the nitrogen-doped graphene-silicon composite particles with good conductivity, high gram capacity and low expansion rate can be prepared, and the battery performance of the lithium ion battery is improved.
The specific type of nitrogen source is not particularly limited according to the embodiments of the present invention, and may be flexibly selected by those skilled in the art according to actual circumstances. In some embodiments, the carbon source is selected from at least one of pyrrole, aniline, urea, pyridine, and thiophene. Therefore, the material has wide sources and low cost, and is favorable for preparing the nitrogen-doped graphene-silicon composite particles with good performance.
According to the embodiment of the invention, after the reaction of the high-pressure reaction kettle is finished, the nitrogen-doped graphene silicon composite particles obtained by the reaction are naturally cooled to room temperature, filtered, and dried in vacuum at 50 ℃ for 24-96 hours. After the nitrogen-doped graphene silicon composite particles are prepared by the method, a plurality of nitrogen-doped graphene silicon composite particles can be bonded together, so that the method further comprises the step of crushing the nitrogen-doped graphene silicon composite particles so as to obtain the nitrogen-doped graphene silicon composite particles with the proper particle size.
S200: a lithium salt layer 30 is formed on the surface of the first composite material by physical vapor deposition so as to obtain the negative electrode material 100, and the schematic structural diagram is shown in fig. 1. The lithium salt layer is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, and meanwhile, the lithium salt layer and the electrolyte have better compatibility, so that the cycle performance of the lithium ion battery can be improved; moreover, the lithium salt layer is prepared by physical vapor deposition, so that the lithium salt layer which is controllable in thickness, high in density and uniformly coated on the surface of the carbon layer can be obtained, and the risk that the carbon layer or graphene silicon composite particles are contacted with electrolyte due to uneven coating of the lithium salt layer is avoided.
According to an embodiment of the present invention, the material of the lithium salt layer is Li 1+(x+y) A x B y Ti 2-(x+y) (PO4) 3 Wherein A is a tetravalent element, B is a divalent element, 0<x is less than or equal to 1 and 0<y is less than or equal to 1, wherein A is selected from at least one of Zr, nb, mo, ce, cr, ge, ru, se, sn, ta, tb, V, W, and B is selected from Mg, zn, cu, ca, sr, ba, cd, fe, mn, ndAt least one of Yb. Therefore, the lithium salt layer is composite lithium salt, so that lithium ions of the lithium ion battery can be transmitted under the condition of high multiplying power, the compatibility of the lithium salt layer 30 made of the material and electrolyte is better, the cycle performance of the lithium ion battery can be improved, and furthermore, various metal elements in the composite lithium salt have a certain synergistic effect, and the conductivity of lithium ions in the lithium salt layer and the structural stability of the lithium salt layer can be improved better.
According to an embodiment of the present invention, the physical vapor deposition conditions are: the temperature is 100-300 ℃ and the vacuum degree is 1 x 10 -4 ～10*10 -4 Pa, the time is 10-120 minutes, and the distance between the target material lithium salt and the first composite material is 1-1000 mm. Thus, a lithium salt layer having a suitable thickness can be produced under the above conditions.
According to the embodiment of the invention, the graphene-silicon composite particles have better conductivity and lower expansion rate, so that the stability of the anode material can be effectively ensured; the surface area of the anode material can be reduced by coating the carbon layer, the first efficiency (first charge and discharge efficiency) of the lithium ion battery is improved, and the gram capacity of the anode material is not influenced by coating the carbon layer; the lithium salt layer is coated to realize the transmission of lithium ions of the lithium ion battery under the condition of high multiplying power, so that the cycle performance of the lithium ion battery can be improved, and meanwhile, the lithium salt layer and the electrolyte have good compatibility so as to improve the stability of the lithium ion battery; moreover, the lithium salt layer is prepared by physical vapor deposition, so that the lithium salt layer which is controllable in thickness, high in density and uniformly coated on the surface of the carbon layer can be obtained, and the risk that the carbon layer or graphene silicon composite particles are contacted with electrolyte due to uneven coating of the lithium salt layer is avoided.
According to the embodiment of the invention, the method for preparing the anode material of the lithium ion battery can be used for preparing the anode material of the lithium ion battery, wherein the requirements of the anode material, the graphene silicon composite particles, the carbon layer, the lithium salt layer and other structures in the preparation method are consistent with the requirements of the anode material, and the requirements are not repeated herein.
In yet another aspect of the invention, a lithium ion battery is provided. According to an embodiment of the invention, the lithium ion battery comprises the anode material. Therefore, the lithium ion battery has better battery performances such as cycle performance, gram capacity, charge and discharge performance, capacitance retention rate and the like. Those skilled in the art will appreciate that the lithium ion battery has all of the features and advantages of the foregoing negative electrode material, and will not be described in detail herein.
Examples
Example 1
The preparation method of the anode material comprises the following steps:
weighing 1000mL of graphene oxide solution with the concentration of 5mg/mL, adding 100mL of copper ammonia solution with the concentration of 0.3mol/L, uniformly stirring, adding 3mL of pyrrole, uniformly stirring, and adding 100mL of 5% aqueous nano silicon solution; transferring the solution into a high-pressure reaction kettle, reacting for 6 hours at the temperature of 180 ℃ under the pressure of 3Mpa, naturally cooling to room temperature, filtering, drying for 48 hours at the temperature of 50 ℃ in vacuum, and crushing to obtain high-density nitrogen-doped graphene-silicon composite particles;
adding 20g of phenolic resin into 500mL of acetone solvent, dissolving and dispersing uniformly, then adding 3g of nitrogen-doped graphene-silicon composite particles, performing ultrasonic dispersion uniformly, and then filtering, carbonizing and crushing to obtain a first composite material of carbon layer coated nitrogen-doped graphene-silicon composite particles;
li is mixed with 1.4 Cr 0.2 Mg 0.2 Ti 1.6 (PO4) 3 Transferring into vacuum coating equipment, depositing multi-element lithium salt on the surface of a first composite material by a magnetron sputtering method to obtain a lithium salt layer with the thickness of 100nm, and then crushing and grading to obtain a negative electrode material, wherein the magnetron sputtering conditions are as follows: temperature 150 ℃ and vacuum degree 3 x 10 -4 Pa, time 60min, and distance between target lithium salt and substrate (i.e. first composite material) 10mm.
The anode material prepared in example 1 was subjected to electron microscope scanning, and as can be seen from fig. 4, the anode material had a particle size of 5 to 20 μm and a relatively uniform size distribution, as can be seen from fig. 4.
Example 2
The preparation method of the anode material comprises the following steps:
weighing 1000mL of graphene oxide solution with the concentration of 1mg/mL, adding 100mL of copper ammonia solution with the concentration of 0.1mol/L, uniformly stirring, adding 1mL of urea, uniformly stirring, and adding 100mL of 1% aqueous nano silicon solution; transferring the solution into a high-pressure reaction kettle, reacting for 12 hours at the temperature of 150 ℃ under the pressure of 3Mpa, naturally cooling to room temperature, filtering, drying for 24 hours at the temperature of 50 ℃ in vacuum, and crushing to obtain high-density nitrogen-doped graphene-silicon composite particles;
adding 10g of epoxy resin into 500mL of N, N-dimethylacetamide solvent, dissolving and dispersing uniformly, adding 1g of nitrogen-doped graphene silicon composite particles, performing ultrasonic dispersion uniformly, filtering, carbonizing and crushing to obtain a first composite material with carbon layers coated with the nitrogen-doped graphene silicon composite particles;
li is mixed with 1.2 Cr 0.1 Sr 0.1 Ti 1.8 (PO4) 3 Transferring into vacuum coating equipment, depositing multi-element lithium salt on the surface of a first composite material by a magnetron sputtering method to obtain a lithium salt layer with the thickness of 10nm, and then crushing and grading to obtain a negative electrode material, wherein the magnetron sputtering conditions are as follows: 100 ℃ and 1 x 10 vacuum degree -4 Pa, time 10min, distance of 1mm between the target lithium salt and the substrate (i.e. the first composite material).
Example 3
The preparation method of the anode material comprises the following steps:
weighing 1000mL of graphene oxide solution with the concentration of 10mg/mL, adding 100mL of copper ammonia solution with the concentration of 0.5mol/L, uniformly stirring, adding 5mL of aniline, uniformly stirring, and adding 100mL of 10% aqueous nano-silicon solution; transferring the solution into a high-pressure reaction kettle, reacting for 2 hours at the temperature of 200 ℃ under the pressure of 3Mpa, naturally cooling to room temperature, filtering, drying for 96 hours at the temperature of 50 ℃ in vacuum, and crushing to obtain high-density nitrogen-doped graphene-silicon composite particles;
adding 30g of melamine into 500mL of n-hexane solvent, dissolving and dispersing uniformly, adding 5g of nitrogen-doped graphene-silicon composite particles, performing ultrasonic dispersion uniformly, and filtering, carbonizing and crushing to obtain a first composite material of carbon layer coated nitrogen-doped graphene-silicon composite particles;
li is mixed with 2.6 Mo 0.8 Mn 0.8 Ti 0.4 (PO4) 3 Transferring into vacuum coating equipment, depositing multi-element lithium salt on the surface of a first composite material by a magnetron sputtering method to obtain a lithium salt layer with the thickness of 10nm, and then crushing and grading to obtain a negative electrode material, wherein the magnetron sputtering conditions are as follows: temperature 300 ℃ and vacuum degree 10 x 10 -4 Pa, time 120min, and distance between the target lithium salt and the substrate (i.e. the first composite material) is 100mm.
Comparative example 1
1000mL of graphene oxide solution with the concentration of 5mg/mL is weighed, and then 100mL of 5% aqueous nano-silicon solution is added; transferring the solution into a high-pressure reaction kettle, reacting for 6 hours at 180 ℃, naturally cooling to room temperature, filtering, drying for 48 hours at 50 ℃ in vacuum, and crushing to obtain the high-density nitrogen-doped graphene-silicon composite particles.
Comparative example 2
The nitrogen-doped graphene silicon composite particles in example 1 were used as a negative electrode material.
Comparative example 3
The first composite material of the carbon layer coated nitrogen-doped graphene silicon composite particles in example 1 was used as a negative electrode material.
Results testing:
1. the specific surface area, tap density, specific capacity and pore diameter of the anode materials obtained in the above examples and comparative examples were tested according to the national standard gbt_245332009 "graphite-based anode materials for lithium ion batteries", while the rate performance and cycle performance of each anode material button cell were tested, and the test results are shown in table 1.
The multiplying power performance testing method comprises the following steps: charging at 1C, 3℃, 5C, 7C and 10C, discharging at 1C, and setting the voltage range at 0.005-2V and the temperature at 25+ -3deg.C;
and (3) testing the cycle performance: 1C charging and 1C discharging, wherein the voltage range is 0.005-2V, and the temperature is 25+/-3 ℃; the number of cycles was 100.
Respectively will implementNegative electrodes were fabricated from the negative electrode materials obtained in examples 1 to 3 and comparative examples 1 to 3 (in the formulation, negative electrode materials, CMC (sodium carboxymethylcellulose), SBR (styrene butadiene rubber), SP (super carbon black) and H) 2 The mass ratio of O is 95:2.5:1.5:1:150), the lithium sheet is used as the positive electrode, and the electrolyte adopts LiPF 6 And (2) EC (ethylene carbonate) +DEC (diethyl carbonate), wherein the volume ratio of electrolyte solvent to DEC=1:1, the diaphragm adopts a composite film of polyethylene PE, polypropylene PP and polyethylene propylene PEP, the button cell is assembled in a glove box filled with hydrogen, the electrochemical performance is carried out on a Wuhan blue electric CT2001A type cell tester, the charging and discharging voltage range is controlled to be 0.005-2.0V, the charging and discharging rate is 0.1C, and finally the button cells A1, A2, A3, B1, B2 and B3 are assembled.
TABLE 1
As can be seen from Table 1, the tap density of the materials prepared in examples 1-3 is significantly higher than that of comparative examples 1-3, because: because the hydrothermal method is used for gasifying the material and then cooling the gasified material to form the material with high density, the first efficiency and the conductivity of the material are improved by depositing lithium salt on the surface of the material, and the specific capacity of the material is improved. Meanwhile, the specific surface area of the nitrogen-doped graphene-silicon composite particles is improved by adopting materials such as graphene oxide as an oxidant, so that the liquid absorption and retention capacity of the cathode material is facilitated. Meanwhile, the negative electrode material has the advantages of high density, strong structural stability and the like, so that the rate capability of the lithium ion battery is improved.
2. And (3) manufacturing a soft package battery:
electrochemical performance test: the negative electrode materials prepared in examples 1 to 3 and comparative examples 1 to 3 were used as negative electrodes, NCM811 was used as positive electrode, the solvent was EC/DEC/PC (propylene carbonate) (wherein EC: DEC: PC=1:1:1) +0.5% vinylene carbonate+1% cyclic methylethyl carbonate (EMC) +0.5% lithium fluoride was used as electrolyte, and the solute was LiPF 6 Celgard 2400 membrane was used as a separator to prepare 5Ah soft pack batteries C1, C2, C3 and D1, D2, D3, respectively.
The negative electrode was then tested for its liquid absorbing capacity, and the cycle performance (2.0C/2.0C) of the battery, and the test results are shown in tables 2 and 3.
Table 2 liquid absorbing ability of negative electrode sheet
As is clear from Table 2, the liquid absorbing and retaining capacities of the negative electrode in examples 1 to 3 are significantly better than those of comparative examples 1 to 3, and the analysis is because: the lithium salt layer on the outer surface of the anode material prepared by the embodiment has good compatibility with electrolyte, so that the liquid absorption and retention capacity of the anode material can be improved.
Table 3 cycle performance of pouch battery
As can be seen from table 3, the cycle performance of the soft pack batteries in examples 1 to 3 was significantly better than that of comparative examples 1 to 3, and the analysis was due to the following: the outer layer of the negative electrode material is coated with a layer of high-density multi-element composite lithium salt, so that the quantity of lithium ions in the lithium ion battery is increased, and the cycle performance of the battery is improved.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (5)

1. A method of preparing a negative electrode material for a lithium ion battery, the negative electrode material comprising: graphene-silicon composite particles; the carbon layer is coated on the surface of the graphene-silicon composite particles; the lithium salt layer is coated on the surface of the carbon layer, which is far away from the graphene-silicon composite particles, and the ratio of the particle size of the graphene-silicon composite particles, the thickness of the carbon layer and the thickness of the lithium salt layer is 100: (1-10): (1-10), wherein the particle size of the anode material is 5-20 microns, and the thickness of the lithium salt layer is 5-100 nanometers; the method for preparing the anode material of the lithium ion battery comprises the following steps: dispersing and mixing graphene-silicon composite particles with an organic carbon source solution, and carbonizing to obtain a first composite material with a carbon layer coating the graphene-silicon composite particles; forming a lithium salt layer on the surface of the first composite material by physical vapor deposition so as to obtain the anode material; the physical vapor deposition conditions are as follows: the temperature is 100-300 ℃ and the vacuum degree is 1 multiplied by 10 -4 ~10×10 - 4 Pa, the time is 10-120 minutes, and the distance between the target lithium salt and the first composite material is 1-1000 mm; the graphene-silicon composite particles are nitrogen-doped graphene-silicon composite particles, graphene oxide dispersion liquid, copper ammonia solution, nitrogen source and aqueous nano-silicon solution are mixed, and the mixed solution is reacted in a high-pressure reaction kettle at 150-200 ℃ for 2-12 hours so as to obtain the nitrogen-doped graphene-silicon composite particles, wherein the dosage of the graphene oxide dispersion liquid is 1000mL, and the concentration is 1-10 mg/mL; the consumption of the copper ammonia solution is 100mL, and the concentration is 0.1-0.5 mol/L; the dosage of the nitrogen source is 1-5 mL; the dosage of the aqueous nano silicon solution is 100mL, and the mass concentration is 1% -10%.
2. The method of claim 1, wherein the mass ratio of the graphene-silicon composite particles to the organic carbon source is 1-5: 10-30.
3. A negative electrode material for a lithium ion battery, characterized in that the negative electrode material is the negative electrode material in the method for producing a negative electrode material for a lithium ion battery according to claim 1.
4. The anode material according to claim 3, wherein the material of the lithium salt layer is Li 1+(x+y) A x B y Ti 2-(x+y) (PO 4 ) 3 Wherein A is a tetravalent element, B is a divalent element, 0<x is less than or equal to 1 and 0<y is less than or equal to 1, wherein A is selected from at least one of Zr, nb, mo, ce, cr, ge, ru, se, sn, ta, tb, V, W, and B is selected from at least one of Mg, zn, cu, ca, sr, ba, cd, fe, mn, nd, yb.
5. A lithium ion battery comprising the negative electrode material according to any one of claims 3 to 4.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101286560A (en) * 2008-05-30 2008-10-15 成都中科来方能源科技有限公司 Composite cathode material for lithium ion cell and preparing method thereof
CN105742569A (en) * 2016-04-07 2016-07-06 湖南杉杉能源科技股份有限公司 Negative pole piece for lithium-ion battery and preparation method of negative pole piece
CN106876689A (en) * 2017-03-24 2017-06-20 中航锂电（洛阳）有限公司 A kind of nitrogen-doped graphene silicon composite cathode material and preparation method thereof, lithium ion battery

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
US20170222219A1 (en) * 2016-01-28 2017-08-03 Dong Sun Ordered nano-porous carbon coating on silicon or silicon/graphene composites as lithium ion battery anode materials

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101286560A (en) * 2008-05-30 2008-10-15 成都中科来方能源科技有限公司 Composite cathode material for lithium ion cell and preparing method thereof
CN105742569A (en) * 2016-04-07 2016-07-06 湖南杉杉能源科技股份有限公司 Negative pole piece for lithium-ion battery and preparation method of negative pole piece
CN106876689A (en) * 2017-03-24 2017-06-20 中航锂电（洛阳）有限公司 A kind of nitrogen-doped graphene silicon composite cathode material and preparation method thereof, lithium ion battery

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